Chapter 3 The Molecules of Life.

Chapter 3 The Molecules of Life

Biology and Society: Got Lactose?
Lactose is the main sugar found in milk. Lactose intolerance is the inability to properly digest lactose. Instead of lactose being broken down and absorbed in the small intestine, lactose is broken down by bacteria in the large intestine, producing gas and discomfort. © 2013 Pearson Education, Inc. 2

Biology and Society: Got Lactose?
Lactose intolerance can be addressed by avoiding foods with lactose or consuming lactase pills along with food. © 2013 Pearson Education, Inc. 3

ORGANIC COMPOUNDS A cell is mostly water.
The rest of the cell consists mainly of carbon-based molecules. Carbon forms large, complex, and diverse molecules necessary for life’s functions. Organic compounds are carbon-based molecules. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers. 4

Carbon Chemistry Carbon is a versatile atom.
It has four electrons in an outer shell that holds eight electrons. Carbon can share its electrons with other atoms to form up to four covalent bonds. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers. 5

Animation: Carbon Skeletons
Carbon Chemistry Carbon can use its bonds to attach to other carbons and form an endless diversity of carbon skeletons varying in size and branching pattern. Animation: Carbon Skeletons © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers. 6

7 Double bond Carbon skeletons vary in length
Figure 3.1 Double bond Carbon skeletons vary in length Carbon skeletons may have double bonds, which can vary in location Carbon skeletons may be unbranched or branched Carbon skeletons may be arranged in rings Figure 3.1 Variations in carbon skeletons 7

Carbon skeletons vary in length
Figure 3.1a Carbon skeletons vary in length Figure 3.1 Variations in carbon skeletons (part 1) 8

Carbon skeletons may have double bonds, which can vary in location
Figure 3.1b Double bond Carbon skeletons may have double bonds, which can vary in location Figure 3.1 Variations in carbon skeletons (part 2) 9

Carbon skeletons may be unbranched
Figure 3.1c Carbon skeletons may be unbranched or branched Figure 3.1 Variations in carbon skeletons (part 3) 10

Carbon skeletons may be arranged in rings
Figure 3.1d Carbon skeletons may be arranged in rings Figure 3.1 Variations in carbon skeletons (part 4) 11

Carbon Chemistry The simplest organic compounds are hydrocarbons, which contain only carbon and hydrogen atoms. The simplest hydrocarbon is methane, a single carbon atom bonded to four hydrogen atoms. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers. 12

13 Structural formula Ball-and-stick model Space-filling model
Figure 3.2 Structural formula Ball-and-stick model Space-filling model Figure 3.2 Methane, the simplest hydrocarbon 13

Carbon Chemistry Larger hydrocarbons form fuels for engines.
Hydrocarbons of fat molecules are important fuels for our bodies. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers. 14

Figure 3.3 Octane Dietary fat Figure 3.3 Hydrocarbons as fuel 15

Carbon Chemistry Each type of organic molecule has a unique three-dimensional shape. The shapes of organic molecules relate to their functions. The unique properties of an organic compound depend on its carbon skeleton and the atoms attached to the skeleton. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers. 16

Carbon Chemistry The groups of atoms that usually participate in chemical reactions are called functional groups. Two common examples are hydroxyl groups (-OH) and carboxyl groups (-COOH). Many biological molecules have two or more functional groups. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers. 17

Giant Molecules from Smaller Building Blocks
On a molecular scale, many of life’s molecules are gigantic, earning the name macromolecules. Three categories of macromolecules are carbohydrates, proteins, and nucleic acids. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers. 18

Most macromolecules are polymers. Polymers are made by stringing together many smaller molecules called monomers. A dehydration reaction links two monomers together and removes a molecule of water. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers. 19

Organisms also have to break down macromolecules. Digestion breaks down macromolecules to make monomers available to your cells. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers.

Hydrolysis breaks bonds between monomers, adds a molecule of water, and reverses the dehydration reaction. Animation: Polymers © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.2 can thus easily be demonstrated (and consumed!) 3. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy supports the role of different functions with different structures. 4. The authors note that a polymer is like a pearl necklace made of many pearl “monomers.” 5. Train cars linking together to form a train is another nice analogy to monomers linking to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus, the reference to water production and a dehydration reaction when linking molecular monomers.

22 (a) Building a polymer chain (b) Breaking a polymer chain
Figure 3.4 H2O OH H Short polymer Monomer Dehydration reaction H2O Hydrolysis OH H Longer polymer (a) Building a polymer chain (b) Breaking a polymer chain Figure 3.4 Synthesis and digestion of polymers 22

(a) Building a polymer chain
Figure 3.4a OH H Short polymer Monomer Dehydration reaction H2O Longer polymer (a) Building a polymer chain Figure 3.4 Synthesis and digestion of polymers (part 1) 23

(b) Breaking a polymer chain
Figure 3.4b H2O Hydrolysis OH H (b) Breaking a polymer chain Figure 3.4 Synthesis and digestion of polymers (part 2) 24

LARGE BIOLOGICAL MOLECULES
There are four categories of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 25

Carbohydrates Carbohydrates include sugars and polymers of sugar. They include small sugar molecules in energy drinks and long starch molecules in spaghetti and French fries. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 26

Carbohydrates In animals, carbohydrates are
a primary source of dietary energy and raw material for manufacturing other kinds of organic compounds. In plants, carbohydrates serve as a building material for much of the plant body. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 27

Monosaccharides Monosaccharides are Common examples are
simple sugars that cannot be broken down by hydrolysis into smaller sugars and the monomers of carbohydrates. Common examples are glucose in sports drinks and fructose found in fruit. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 28

Both glucose and fructose are found in honey.
Monosaccharides Both glucose and fructose are found in honey. Glucose and fructose are isomers, molecules that have the same molecular formula but different structures. Animation: L-Dopa Animation: Isomers © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 29

30 C6H12O6 C6H12O6 Glucose Fructose Isomers Figure 3.5
Figure 3.5 Monosaccharides (simple sugars) 30

C6H12O6 C6H12O6 31 Glucose Fructose Isomers Figure 3.5a
Figure 3.5 Monosaccharides (simple sugars) (detail) 31

Monosaccharides are the main fuels for cellular work.
In water, many monosaccharides form rings. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 32

33 (a) Linear and ring structures (b) Abbreviated ring structure
Figure 3.6 (a) Linear and ring structures (b) Abbreviated ring structure Figure 3.6 The ring structure of glucose 33

(a) Linear and ring structures
Figure 3.6a (a) Linear and ring structures Figure 3.6 The ring structure of glucose (part 1) 34

(b) Abbreviated ring structure 35 Figure 3.6b
Figure 3.6 The ring structure of glucose (part 2) 35

Animation: Disaccharides
A disaccharide is a double sugar, constructed from two monosaccharides, and formed by a dehydration reaction. Animation: Disaccharides © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 36

37 Glucose Galactose Lactose H OH H2O Figure 3.7
Figure 3.7 Disaccharide (double sugar) formation 37

Glucose Galactose Lactose 38 H OH H2O Figure 3.7a
Figure 3.7 Disaccharide (double sugar) formation (detail) 38

Disaccharides include
lactose in milk, maltose in beer, malted milk shakes, and malted milk ball candy, and sucrose in table sugar. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 39

High-fructose corn syrup is made by a commercial process that converts
Disaccharides Sucrose is the main carbohydrate in plant sap and rarely used as a sweetener in processed foods in the United States. High-fructose corn syrup is made by a commercial process that converts natural glucose in corn syrup to much sweeter fructose. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 40

41 processed to extract Starch broken down into Glucose
Figure 3.8 processed to extract Starch broken down into Glucose converted to sweeter Fructose added to foods as high-fructose corn syrup Figure 3.8 High-fructose corn syrup 41

The average American consumes
Disaccharides The United States is one of the world’s leading markets for sweeteners. The average American consumes about 45 kg of sugar (about 100 lb) per year, mainly as sucrose and high-fructose corn syrup. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 42

Animation: Polysaccharides
Polysaccharides are complex carbohydrates made of long chains of sugar units—polymers of monosaccharides. Animation: Polysaccharides © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 43

44 Starch granules in potato tuber cells (a) Starch Glucose monomer
Figure 3.9 Starch granules in potato tuber cells (a) Starch Glucose monomer Glycogen granules in muscle tissue (b) Glycogen Cellulose microfibrils in a plant cell wall (c) Cellulose Cellulose molecules Hydrogen bonds Figure 3.9 Polysaccharides 44

Potatoes and grains are major sources of starch in our diet.
Polysaccharides Starch is a familiar example of a polysaccharide, is used by plant cells to store energy, and consists of long strings of glucose monomers. Potatoes and grains are major sources of starch in our diet. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 45

Starch granules in potato tuber cells 46 Figure 3.9a
Figure 3.9 Polysaccharides (micrograph of starch granules) 46

Polysaccharides Glycogen is used by animals cells to store energy and
converted to glucose when it is needed. © 2013 Pearson Education, Inc. 47

Glycogen granules in muscle tissue 48 Figure 3.9b
Figure 3.9 Polysaccharides (micrograph of glycogen granules) 48

Polysaccharides Cellulose
is the most abundant organic compound on Earth, forms cable-like fibrils in the walls that enclose plant cells, and cannot be broken apart by most animals. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 49

Cellulose microfibrils in a plant cell wall
Figure 3.9c Cellulose microfibrils in a plant cell wall Cellulose molecules Figure 3.9 Polysaccharides (micrograph of cellulose microfibrils) 50

51 (a) Starch Glucose monomer (b) Glycogen (c) Cellulose
Figure 3.9d (a) Starch Glucose monomer (b) Glycogen (c) Cellulose Hydrogen bonds Figure 3.9 Polysaccharides (detail of glycosidic bonds) 51

Monosaccharides and disaccharides dissolve readily in water.
Polysaccharides Monosaccharides and disaccharides dissolve readily in water. Cellulose does not dissolve in water. Almost all carbohydrates are hydrophilic, or “water-loving,” adhering water to their surface. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 52

Lipids Lipids are neither macromolecules nor polymers and
hydrophobic, unable to mix with water. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 53

Vinegar (hydrophilic)
Figure 3.10 Oil (hydrophobic) Vinegar (hydrophilic) Figure 3.10 The separation of hydrophobic (oil) and hydrophilic (vinegar) components in salad dressing 54

A typical fat, or triglyceride, consists of
Fats A typical fat, or triglyceride, consists of a glycerol molecule, joined with three fatty acid molecules, via a dehydration reaction. Animation: Fats © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 55

56 H HO Fatty acid H2O Glycerol
Figure 3.11 H HO Fatty acid H2O Glycerol (a) A dehydration reaction linking a fatty acid to glycerol (b) A fat molecule with a glycerol “head” and three energy-rich hydrocarbon fatty acid “tails” Figure 3.11 The synthesis and structure of a triglyceride molecule 56

Figure 3.11a H HO Fatty acid H2O Glycerol (a) A dehydration reaction linking a fatty acid to glycerol Figure 3.11 The synthesis and structure of a triglyceride molecule (part 1) 57

58 (b) A fat molecule with a glycerol “head” and three
Figure 3.11b (b) A fat molecule with a glycerol “head” and three energy-rich hydrocarbon fatty acid “tails” Figure 3.11 The synthesis and structure of a triglyceride molecule (part 2) 58

Fats perform essential functions in the human body including
energy storage, cushioning, and insulation. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 59

If the carbon skeleton of a fatty acid
Fats If the carbon skeleton of a fatty acid has fewer than the maximum number of hydrogens, it is unsaturated; if it has the maximum number of hydrogens, it is saturated. A saturated fat has no double bonds and all three of its fatty acids saturated. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 60

Fats Most animal fats have a high proportion of saturated fatty acids,
can easily stack, tending to be solid at room temperature, and contribute to atherosclerosis, in which lipid-containing plaques build up along the inside walls of blood vessels. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 61

Most plant and fish oils tend to be
Fats Most plant and fish oils tend to be high in unsaturated fatty acids and liquid at room temperature. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 62

Fats Hydrogenation adds hydrogen,
converts unsaturated fats to saturated fats, makes liquid fats solid at room temperature, and creates trans fat, a type of unsaturated fat that is particularly bad for your health. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 63

64 TYPES OF FATS Saturated Fats Unsaturated Fats Margarine Trans fats
Figure 3.12 TYPES OF FATS Saturated Fats Unsaturated Fats Margarine Plant oils Trans fats Omega-3 fats Figure 3.12 Types of fats 64

Figure 3.12a Saturated Fats Figure 3.12 Types of fats (part 1) 65

Unsaturated Fats 66 Margarine Trans fats Omega-3 fats Plant oils
Figure 3.12b Unsaturated Fats Margarine Trans fats Plant oils Omega-3 fats Figure 3.12 Types of fats (part 2) 66

Steroids are very different from fats in structure and function.
The carbon skeleton is bent to form four fused rings. Steroids vary in the functional groups attached to this set of rings, and these chemical variations affect their function. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 67

Steroids Cholesterol is a key component of cell membranes and
the “base steroid” from which your body produces other steroids, such as estrogen and testosterone. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 68

69 Cholesterol can be converted by the body to Testosterone
Figure 3.13 Cholesterol can be converted by the body to Testosterone A type of estrogen Figure 3.13 Examples of steroids 69

Synthetic anabolic steroids
are variants of testosterone, mimic some of its effects, can cause serious physical and mental problems, may be prescribed to treat diseases such as cancer and AIDS, and are abused by athletes to enhance performance. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 70

Steroids Most athletic organizations now ban the use of anabolic steroids because of their health hazards and unfairness, by providing an artificial advantage. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 71

Figure 3.14 THG Figure 3.14 Steroids and the modern athlete 72

Proteins Proteins are polymers constructed from amino acid monomers,
account for more than 50% of the dry weight of most cells, perform most of the tasks required for life, and form enzymes, chemicals that change the rate of a chemical reaction without being changed in the process. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 73

74 MAJOR TYPES OF PROTEINS Structural Proteins (provide support)
Figure 3.15 MAJOR TYPES OF PROTEINS Structural Proteins (provide support) Storage Proteins (provide amino acids for growth) Contractile Proteins (help movement) Transport Proteins (help transport substances) Enzymes (help chemical reactions) Figure 3.15 Some types of proteins 74

75 Structural Proteins (provide support) Figure 3.15a
Figure 3.15 Some types of proteins (part 1) 75

76 Storage Proteins (provide amino acids for growth) Figure 3.15b

77 Contractile Proteins (help movement) Figure 3.15c

78 Transport Proteins (help transport substances) Figure 3.15d

79 Enzymes (help chemical reactions) Figure 3.15e

The Monomers of Proteins: Amino Acids
All proteins are macromolecules constructed from a common set of 20 kinds of amino acids. Each amino acid consists of a central carbon atom bonded to four covalent partners. Three of those attachment groups are common to all amino acids: a carboxyl group (-COOH), an amino group (-NH2), and a hydrogen atom. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 80

81 Amino group Carboxyl group The general structure of an amino acid
Figure 3.16 Amino group Carboxyl group Side group The general structure of an amino acid Hydrophobic side group Hydrophilic side group Leucine Serine Figure 3.16 Amino acids 81

82 Amino Carboxyl group group The general structure of an amino acid
Figure 3.16a Amino group Carboxyl group Side group The general structure of an amino acid Figure 3.16 Amino acids (part 1) 82

83 Hydrophobic side group Hydrophilic side group Leucine Serine
Figure 3.16b Hydrophobic side group Hydrophilic side group Leucine Serine Figure 3.16 Amino acids (part 2) 83

Animation: Protein Structure Introduction
Proteins as Polymers Cells link amino acids together by dehydration reactions, forming peptide bonds, and creating long chains of amino acids called polypeptides. Animation: Protein Structure Introduction © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 84

85 OH H Carboxyl Amino Figure 3.17-1
Figure 3.17 Joining amino acids (step 1) 85

86 OH H H2O Carboxyl Amino Dehydration reaction Peptide bond
Figure Carboxyl Amino OH H H2O Dehydration reaction Peptide bond Figure 3.17 Joining amino acids (step 2) 86

Your body has tens of thousands of different kinds of protein.
Proteins as Polymers Your body has tens of thousands of different kinds of protein. Proteins differ in their arrangement of amino acids. The specific sequence of amino acids in a protein is its primary structure. Animation: Primary Protein Structure Blast Animation: Protein Primary Structure © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 87

Figure 3.18 1 5 15 10 35 30 25 20 45 40 50 55 65 60 70 85 80 75 Amino acid 95 100 90 110 115 105 125 120 129 Figure 3.18 The primary structure (amino acid sequence) of a protein 88

Proteins as Polymers A slight change in the primary structure of a protein affects its ability to function. The substitution of one amino acid for another in hemoglobin causes sickle-cell disease, an inherited blood disorder. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 89

90 Normal red blood cell Normal hemoglobin Sickled red blood cell
Figure 3.19 SEM Glu Glu Val Pro His Leu Thr 6 1 5 2 3 4 Normal red blood cell Normal hemoglobin SEM Glu Val Val Pro His Leu Thr 6 1 5 2 3 4 Sickled red blood cell Sickle-cell hemoglobin Figure 3.19 A single amino acid substitution in a protein causes sickle-cell disease. 90

A functional protein consists of
Protein Shape A functional protein consists of one or more polypeptide chains, precisely twisted, folded, and coiled into a molecule of unique shape. Blast Animation: Alpha Helix Blast Animation: Protein Secondary Structure Animation: Secondary Protein Structure © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 91

Proteins consisting of one polypeptide have three levels of structure.
Protein Shape Proteins consisting of one polypeptide have three levels of structure. Proteins consisting of more than one polypeptide chain have a fourth level, quaternary structure. Blast Animation: Protein Tertiary and Quaternary Structure Animation: Tertiary Protein Structure Animation: Quaternary Protein Structure © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 92

93 (b) Secondary structure (c) Tertiary structure (d) Quaternary
Figure Amino acids (b) Secondary structure (c) Tertiary structure (d) Quaternary structure (a) Primary structure Pleated sheet A protein with four polypeptide subunits Hydrogen bond Polypeptide Alpha helix Figure 3.20 The four levels of protein structure (step 4) 93

A protein’s three-dimensional shape
Protein Shape A protein’s three-dimensional shape typically recognizes and binds to another molecule and enables the protein to carry out its specific function in a cell. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 94

Figure 3.21 Target Protein Figure 3.21 A computer model showing a protein (purple) about to bind to its target (red) 95

What Determines Protein Shape?
A protein’s shape is sensitive to the surrounding environment. An unfavorable change in temperature and/or pH can cause denaturation of a protein, in which it unravels and loses its shape. High fevers (above 104F) in humans can cause some proteins to denature. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 96

What Determines Protein Shape?
Misfolded proteins are associated with Alzheimer’s disease, mad cow disease, and Parkinson’s disease. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 97

Nucleic Acids Nucleic acids are macromolecules that store information,
provide the directions for building proteins, and include DNA and RNA. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 98

Nucleic Acids DNA resides in cells in long fibers called chromosomes.
A gene is a specific stretch of DNA that programs the amino acid sequence of a polypeptide. The chemical code of DNA must be translated from “nucleic acid language” to “protein language.” © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 99

100 Gene DNA Nucleic acids RNA Amino acid Protein Figure 3.22
Figure 3.22 Building a protein 100

Nucleic Acids Nucleic acids are polymers made from monomers called nucleotides. Each nucleotide has three parts: a five-carbon sugar, a phosphate group, and a nitrogen-containing base. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 101

102 group (a) Atomic structure (b) Symbol used in this book
Figure 3.23 Nitrogenous base (A, G, C, or T) Thymine (T) Phosphate group Phosphate Base T Sugar (deoxyribose) Sugar (a) Atomic structure (b) Symbol used in this book Figure 3.23 A DNA nucleotide 102

(a) Atomic structure 103 Nitrogenous base (A, G, C, or T) Thymine (T)
Figure 3.23a Nitrogenous base (A, G, C, or T) Thymine (T) Phosphate group Sugar (deoxyribose) (a) Atomic structure Figure 3.23 A DNA nucleotide (detail) 103

Nucleic Acids Each DNA nucleotide has one of four possible nitrogenous bases: adenine (A), guanine (G), thymine (T), or cytosine (C). © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 104

105 Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Adenine (A)
Figure 3.24 Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Space-filling model of DNA Figure 3.24 The nitrogenous bases of DNA 105

106 Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Figure 3.24a
Figure 3.24 The nitrogenous bases of DNA (part 1) 106

107 Adenine (A) Guanine (G) Thymine (T) Cytosine (C)
Figure 3.24b Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Space-filling model of DNA Figure 3.24 The nitrogenous bases of DNA (part 2) 107

Nucleic Acids Dehydration reactions
link nucleotide monomers into long chains called polynucleotides, form covalent bonds between the sugar of one nucleotide and the phosphate of the next, and form a sugar-phosphate backbone. Nitrogenous bases hang off the sugar-phosphate backbone. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 108

Nucleic Acids Two strands of DNA join together to form a double helix.
Bases along one DNA strand hydrogen-bond to bases along the other strand. The functional groups hanging off the base determine which bases pair up: A only pairs with T and G can only pair with C. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 109

110 (a) DNA strand (b) Double helix (polynucleotide)
Figure 3.25 C G Sugar-phosphate backbone T A Base pair A T Nucleotide T Hydrogen bond G A A T C A T A G Bases T C G A T (a) DNA strand (polynucleotide) (b) Double helix (two polynucleotide strands) Figure 3.25 The structure of DNA 110

Nucleic Acids RNA, ribonucleic acid, is different from DNA.
RNA uses the sugar ribose and the base uracil (U) instead of thymine (T). RNA is usually single-stranded, but DNA usually exists as a double helix. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 111

Nitrogenous base (A, G, C, or U) Phosphate group Sugar (ribose)
Figure 3.26 Nitrogenous base (A, G, C, or U) Uracil (U) Phosphate group Sugar (ribose) Figure 3.26 An RNA nucleotide 112

The Process of Science: Does Lactose Intolerance Have a Genetic Basis?
Observation: Most lactose-intolerant people have a normal version of the lactase gene. Question: What is the genetic basis for lactose intolerance? Hypothesis: Lactose-intolerant people have a mutation but not within the lactase gene. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 113

The Process of Science: Does Lactose Intolerance Have a Genetic Basis?
Prediction: A mutation would be found near the lactase gene. Experiment: Genes of 196 lactose-intolerant people were examined. Results: Researchers found a 100% correlation between lactose intolerance and a nucleotide at a site approximately 14,000 nucleotides away from the lactase gene. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 114

115 DNA Lactase gene C or T Human Chromosome 2 Section cell of
Figure 3.27 DNA Lactase gene C or T Human cell Chromosome 2 Section of chromosome 2 Figure 3.27 A genetic cause of lactose intolerance 115

Evolution Connection: The Evolution of Lactose Intolerance in Humans
Most people are lactose-intolerant as adults. Lactose intolerance is found in 80% of African Americans and Native Americans, 90% of Asian Americans, but only 10% of Americans of northern European descent. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 116

Evolution Connection: The Evolution of Lactose Intolerance in Humans
Lactose tolerance appears to have evolved in northern European cultures that relied upon dairy products. Ethnic groups in East Africa that rely upon dairy products are also lactose tolerant but due to different mutations. © 2013 Pearson Education, Inc. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on your head remains flexible because of oils produced in your scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world. 3. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. 4. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey an advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references; for example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). 2. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen (yields) water + usable energy (used to build ATP) + heat + exhaled CO2. 3. The section about our use of sugars may be of considerable interest to your students, who might not be expecting much interest in a lecture about organic chemistry. Consider an assignment for each student to bring to class a product label indicating high-fructose corn syrup (HFCS) as an ingredient. 4. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates. 5. Consider an assignment for students to find reliable sources that discuss high sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider narrowing down the categories to certain nonprofit health organizations (American Cancer Society, American Heart Association, and the like) and peer-reviewed journals. 6. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 7. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper). 8. An adult human may store about a half of a kilogram of glycogen in the liver and muscles of the body, depending on recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors). 9. Another simple demonstration can illustrate hydrophobic and hydrophilic substances. In front of the class, mix colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made that remains separated; however, the dyes may bleed between the oil and the water.) 10. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Perhaps your students can find references to this correlation on the Internet. 11. Many analogies relate to students the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words”, creating even more diversity. Another analogy is to trains. This builds on the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20100, a number beyond imagination. 12. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex! 13. Most cooking results in changes in the texture and color of a food. The brown color of a steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked. 14. Consider this assignment to wrap up the presence of organic molecules in our diets. Have students working individually or in small groups analyze a food label listing the components of a McDonald’s Big Mac. Note the most abundant organic molecule class (perhaps by weight) found in each component. 15. The “NA” in DNA and RNA represents ‘nucleic acid”. Students often do not make this association without assistance. 117

118 H2O H2O Dehydration OH H Short polymer Monomer Hydrolysis
Figure 3.UN01 H2O Dehydration OH H Short polymer Monomer Hydrolysis Longer polymer H2O Figure 3.UN01 Summary of Key Concepts: Giant Molecules from Smaller Building Blocks 118

119 Large biological molecules Functions Components Examples
Figure 3.UN02 Large biological molecules Functions Components Examples Monosaccharides: glucose, fructose; Disaccharides: lactose, sucrose; Polysaccharides: starch, cellulose Dietary energy; storage; plant structure Carbohydrates Monosaccharide Long-term energy storage (fats); hormones (steroids) Fats (triglycerides); steroids (testosterone, estrogen) Lipids Components of a triglyceride Enzymes, structure, storage, contraction, transport, etc. Lactase (an enzyme); hemoglobin (a transport protein) Proteins Side group Amino acid Information storage Nucleic acids T DNA, RNA Nucleotide Figure 3.UN02 Summary of Key Concepts: Large Biological Molecules 119

Carbohydrates Functions Components Examples 120 Monosaccharides:
Figure 3.UN02a Carbohydrates Functions Components Examples Monosaccharides: glucose, fructose: Disaccharides: lactose, sucrose: Polysaccharides: starch, cellulose Dietary energy; storage; plant structure Monosaccharide Figure 3.UN02 Summary of Key Concepts: Large Biological Molecules (part 1) 120

Lipids Functions Components Examples 121 Long-term energy storage
Figure 3.UN02b Lipids Functions Components Examples Long-term energy storage (fats); hormones (steroids) Fats (triglycerides); steroids (testosterone, estrogen) Fatty acid Glycerol Components of a triglyceride Figure 3.UN02 Summary of Key Concepts: Large Biological Molecules (part 2) 121

Proteins Functions Components Examples 122 Enzymes, structure, Lactase
Figure 3.UN02c Proteins Functions Components Examples Amino group Carboxyl group Enzymes, structure, storage, contraction, transport, etc. Lactase (an enzyme); hemoglobin (a transport protein) Side group Amino acid Figure 3.UN02 Summary of Key Concepts: Large Biological Molecules (part 3) 122

Nucleic acids Functions Components Examples 123 Information storage
Figure 3.UN02d Nucleic acids Functions Components Examples Phosphate Base Information storage T DNA, RNA Sugar Nucleotide Figure 3.UN02 Summary of Key Concepts: Large Biological Molecules (part 4) 123

124 Primary structure Secondary structure Tertiary structure
Figure 3.UN03 Primary structure Secondary structure Tertiary structure Quaternary structure Figure 3.UN03 Summary of Key Concepts: Proteins 124

125 DNA double helix DNA strand DNA nucleotide T A C Base G Phosphate
Figure 3.UN04 T A C Base G Phosphate group T Sugar DNA double helix DNA strand DNA nucleotide Figure 3.UN04 Summary of Key Concepts: Nucleic Acids 125

Chapter 3 The Molecules of Life.

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Chapter 3 The Molecules of Life.

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