© 2010 Pearson Education, Inc. Lectures by Chris C. Romero, updated by Edward J. Zalisko PowerPoint ® Lectures for Campbell Essential Biology, Fourth Edition – Eric Simon, Jane Reece, and Jean Dickey Campbell Essential Biology with Physiology, Third Edition – Eric Simon, Jane Reece, and Jean Dickey Chapter 2 The Molecules of Life

© 2010 Pearson Education, Inc. Table 2-2, p. 29

© 2010 Pearson Education, Inc. 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.

© 2010 Pearson Education, Inc. Compounds  Organic compounds  Inorganic compounds

© 2010 Pearson Education, Inc. Carbon Chemistry Carbon is a versatile atom. –It has four electrons in an outer shell that holds eight. –Carbon can share its electrons with other atoms to form up to four covalent bonds.

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

Structural formula Methane Ball-and-stick modelSpace-filling model Figure 3.2

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Figure 3.3

© 2010 Pearson Education, Inc. Important organic molecules in cells 1. Carbohydrates

© 2010 Pearson Education, Inc. a. monosaccharides examples –Glucose in sports drinks –Fructose found in fruit

© 2010 Pearson Education, Inc. b. disaccharide examples –Lactose in milk –Maltose in beer, malted milk shakes, and malted milk ball candy –Sucrose in table sugar

© 2010 Pearson Education, Inc. Condensation reaction

© 2010 Pearson Education, Inc. Hydrolysis reaction

Glucose Galactose Lactose Figure 3.7

processed to extract broken down into converted to sweeter added to foods as high-fructose corn syrup Starch Glucose Fructose Ingredients: carbonated water, high-fructose corn syrup, caramel color, phosphoric acid, natural flavors Figure 3.8

© 2010 Pearson Education, Inc. The United States is one of the world’s leading markets for sweeteners. –The average American consumes about 45 kg of sugar (about 100 lbs.) per year.

© 2010 Pearson Education, Inc. c. Polysaccharides

Glucose monomer  a  Starch  b  Glycogen  c  Cellulose Starch granules Glycogen granules Cellulose fibril Cellulose molecules Figure 3.9

© 2010 Pearson Education, Inc. Important organic molecules in cells 1. Carbohydrates- composed of sugar units 2. Lipids

Oil (hydrophobic) Vinegar (hydrophilic) Figure 3.10

Fatty acid 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 Triglyceride

© 2010 Pearson Education, Inc. a. saturated fat b. unsaturated fat

© 2010 Pearson Education, Inc. Saturated fat Contribute to atherosclerosis, a condition in which lipid- containing plaques build up within the walls of blood vessels

© 2010 Pearson Education, Inc. Hydrogenation- creates trans fats –Adds hydrogen –Converts unsaturated fats to saturated fats –Makes liquid fats solid at room temperature

© 2010 Pearson Education, Inc. Fig. 2-1, p. 20 trans fatty acid

Saturated Fats TYPES OF FATS Unsaturated Fats Margarine Plant oils Trans fats Omega-3 fats INGREDIENTS: SOYBEAN OIL, FULLY HYDROGENATED COTTONSEED OIL, PARTIALLY HYDROGENATED COTTONSEED OIL AND SOYBEAN OILS, MONO AND DIGLYCERIDES, TBHO AND CITRIC ACID ANTIOXIDANTS Figure 3.12

© 2010 Pearson Education, Inc. Fig. 2-15, p. 32 hydrophilic head two hydropho bic tails A one layer of lipids B a lipid bilayer

© 2010 Pearson Education, Inc. c. steroids/ cholesterol Steroids are very different from fats in structure and function. –The carbon skeleton is bent to form four fused rings Cholesterol - key component of cell membranes –The “base steroid” from which your body produces other steroids, such as estrogen and testosterone

Cholesterol TestosteroneA type of estrogen Figure 3.13

© 2010 Pearson Education, Inc. Synthetic anabolic steroids –Resemble testosterone –Mimic some of its effects –Can cause liver damage, rise in cholesterol and infertility –Are abused by athletes to enhance performance

© 2010 Pearson Education, Inc. Important organic molecules in cells 1. Carbohydrates- composed of sugar units 2. Lipids- composed of glycerol and fatty acids 3. Proteins

 a  The general structure of an amino acid Amino group Carboxyl group LeucineSerine Side group Figure 3.16

Amino group Carboxyl group Side group Side group Amino acid Side group Side group Dehydration reaction Peptide bond Figure

 a  Primary structure  b  Secondary structure Amino acids Pleated sheet Alpha helix  c  Tertiary structure Polypeptide  d  Quaternary structure Protein with four polypeptides Figure

© 2010 Pearson Education, Inc. Proteins –Perform most of the tasks the body needs to function –Form enzymes, chemicals that change the rate of a chemical reaction

MAJOR TYPES OF PROTEINS Structural ProteinsStorage Proteins Contractile ProteinsTransport ProteinsEnzymes Figure 3.15

© 2010 Pearson Education, Inc. Animation 3-2  proteins

© 2010 Pearson Education, Inc. Important organic molecules in cells 1. Carbohydrates- composed of sugar units 2. Lipids- composed of glycerol and fatty acids 3. Proteins- composed of amino acids 4. Nucleic acids

Gene DNA RNA Protein Amino acid Nucleic acids Figure 3.22

Figure 3.23 Nitrogenous base  A, G, C, or T  Thymine  T  Phosphate group Sugar  deoxyribose   a  Atomic structure  b  Symbol used in this book Phosphate Base Sugar

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Adenine  A  Guanine  G  Thymine  T  Cytosine  C  Adenine  A  Guanine  G  Thymine  T  Cytosine  C  Space-filling model of DNA Figure 3.24

© 2010 Pearson Education, Inc. Animation 3-3  nucleic acids

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