STRUCTURE & FUNCTION OF LARGE BIOLOGICAL MOLECULES (MACROMOLECULES)

Concept 2.1: Macromolecules are polymers, built from monomers – Carbohydratesamino acids – Proteinsmonosaccharides – Nucleic acidslipids – Do not form polymersnucleotides Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 1. Match the polymer to its monomer

2. Number the carbons properly

3. To link these 2 monosaccharides together, what do you do? 4. What is the process called that will link the 2 together to make a disaccharide?

5. What is this sugar called? 6. Suppose 2 more monosaccharides link to the diagram below, what would the carbohydrate be called? 7. How many total water molecules would need to be removed to have 4 monosaccharides linked together? 8.Between which two carbons does this process always occur when covalently bonding monosaccharides together? Use the carbon numbering system to figure this out.

Concept 5.1: Macromolecules are polymers, built from monomers A polymer is a long molecule consisting of many similar building blocks These small building-block molecules are called monomers Three of the four classes of life’s organic molecules are polymers: – Carbohydrates – Proteins – Nucleic acids Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Concept 2.2: Carbohydrates serve as fuel and building material Carbohydrates include sugars and the polymers of sugars The simplest carbohydrates are monosaccharides, or single sugars. They provide ready energy for the body. Carbohydrate macromolecules are polysaccharides, polymers composed of many sugar building blocks Polysacchrides – fuel that “burns” more slowly. More bonds for the body to break (hydrolysis). Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Sugars Monosaccharides have molecular formulas that are usually multiples of CH 2 O Glucose (C 6 H 12 O 6 ) is the most common monosaccharide Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-4b (b) Abbreviated ring structure

A disaccharide is formed when a dehydration synthesis joins two monosaccharides Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-5 (b) Dehydration reaction in the synthesis of sucrose GlucoseFructose Sucrose MaltoseGlucose (a) Dehydration reaction in the synthesis of maltose 1–2 glycosidic linkage Dehydration synthesis: remove water make a bond

Polysaccharides Polysaccharides, the polymers of sugars, have storage and structural roles Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Storage Polysaccharides Starch, a storage polysaccharide of plants, consists entirely of glucose monomers Plants store surplus starch as granules within chloroplasts and other plastids Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-6 (b) Glycogen: an animal polysaccharide Starch Glycogen Amylose Chloroplast (a) Starch: a plant polysaccharide Amylopectin Mitochondria Glycogen granules 0.5 µm 1 µm

Glycogen is a storage polysaccharide in animals Humans and other vertebrates store glycogen mainly in liver and muscle cells Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Structural Polysaccharides The polysaccharide cellulose is a major component of the tough wall of plant cells Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-7a  Glucose Glucose: a monosaccharide. It’s only 1 ring!

Fig. 5-7bc (a) Starch: a linkage of glucose molecules (b) Cellulose: same thing but a little different!! Doesn’t seem like much: but it makes Cellulose less digestible than.

Fig. 5-8 b Glucose monomer Cellulose molecules Microfibril Cellulose microfibrils in a plant cell wall 0.5 µm 10 µm Cell walls The reason you can’t graze on the front lawn of the school like a cow during lunch!!

Enzymes that digest starch (amylase) can’t break bonds in cellulose Cellulose in human food passes through the digestive tract as insoluble fiber Some microbes use enzymes to digest cellulose Many herbivores, from cows to termites, have symbiotic relationships with these microbes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-9

Chitin, another structural polysaccharide, is found in the exoskeleton of arthropods Chitin also provides structural support for the cell walls of many fungi Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig The structure of the chitin monomer. (a) (b) (c) Chitin forms the exoskeleton of arthropods. Chitin is used to make a strong and flexible surgical thread. Hey look, chitin’s got some nitrogen Other carbs don’t have that.

Concept 5.3: Lipids are a diverse group of hydrophobic molecules Lipids are the one class of large biological molecules that do not form polymers Lipids are hydrophobic & form nonpolar covalent bonds The most biologically important lipids are fats, phospholipids, and steroids, waxes & oils Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fats Fats are constructed from two types of smaller molecules: glycerol and 3 fatty acids Glycerol is a three-carbon alcohol with a hydroxyl group attached to each carbon A fatty acid consists of a carboxyl group attached to a long carbon skeleton Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-11a Fatty acid (palmitic acid) (a) Dehydration reaction in the synthesis of a fat Glycerol

Fig. 5-11b (b) Fat molecule

Saturated fatty acids have the maximum number of hydrogen atoms possible and no double bonds Unsaturated fatty acids have one or more double bonds Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-12a (a) Saturated fat Structural formula of a saturated fat molecule Stearic acid, a saturated fatty acid

Fig. 5-12b (b) Unsaturated fat Structural formula of an unsaturated fat molecule Oleic acid, an unsaturated fatty acid double bond causes bending

Fats made from saturated fatty acids are called saturated fats, and are solid at room temperature Most animal fats are saturated Fats made from unsaturated fatty acids are called unsaturated fats or oils, and are liquid at room temperature Plant fats and fish fats are usually unsaturated Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

A diet rich in saturated fats may contribute to cardiovascular disease through plaque deposits Hydrogenation is the process of converting unsaturated fats to saturated fats by adding hydrogen (This is bad for you!!) Trans fats may contribute more than saturated fats to cardiovascular disease Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The major function of fats is energy storage Humans and other mammals store their fat in adipose cells Adipose tissue also cushions vital organs and insulates the body Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Phospholipids In a phospholipid, two fatty acids and a phosphate group are attached to glycerol The two fatty acid tails are hydrophobic, but the phosphate group and its attachments form a hydrophilic head Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig (b)(a)(c) Structural formula Phospholipid symbol Fatty acids Hydrophilic head Hydrophobic tails Phosphate Hydrophobic tails Hydrophilic head Let’s use Diagram C. It’s easy to Understand!

When phospholipids are added to water, they self-assemble into a bilayer, with the hydrophobic tails pointing toward the interior Phospholipids are the major component of all cell membranes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig Hydrophilic head Hydrophobic tail WATER

Steroids Steroids are lipids characterized by a carbon skeleton consisting of four fused rings Cholesterol, an important steroid, is a component in animal cell membranes Although cholesterol is essential in animals, high levels in the blood may contribute to cardiovascular disease Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-15

Concept 5.4: Proteins have many structures, resulting in a wide range of functions Proteins account for more than 50% of the dry mass of most cells Protein functions include structural support, storage, transport, cellular communications, movement, and defense against foreign substances Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Table 5-1

Enzymes are a type of protein that acts as a catalyst to speed up chemical reactions Enzymes can perform their functions repeatedly, functioning as workhorses that carry out the processes of life Enzymes have specific shapes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig Enzyme (sucrase) Substrate (sucrose) Fructose Glucose OH H O H2OH2O

Polypeptides Polypeptides are polymers built from the same set of 20 amino acids A protein consists of one or more polypeptides Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Amino Acid Monomers Amino acids are organic molecules with carboxyl (-COOH) and amino groups (NH 2 ) COOH and NH 2 are functional groups and make the molecule an amino acid. Amino acids differ in their properties due to differing side chains, called R groups Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-UN1 Amino group Carboxyl group  carbon

Fig Nonpolar Glycine (Gly or G) Alanine (Ala or A) Valine (Val or V) Leucine (Leu or L) Isoleucine (Ile or I) Methionine (Met or M) Phenylalanine (Phe or F) Trypotphan (Trp or W) Proline (Pro or P) Polar Serine (Ser or S) Threonine (Thr or T) Cysteine (Cys or C) Tyrosine (Tyr or Y) Asparagine (Asn or N) Glutamine (Gln or Q) Electrically charged AcidicBasic Aspartic acid (Asp or D) Glutamic acid (Glu or E) Lysine (Lys or K) Arginine (Arg or R) Histidine (His or H) Don’t get worked up about these. Appreciate them!! These are amino acids. There are 20. They bond together by peptide bonds to make up all proteins!

Amino Acid Polymers Amino acids are linked by special covalent bonds called peptide bonds A polypeptide is a polymer of amino acids Each polypeptide has a unique linear sequence of amino acids Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Peptide bond Fig Peptide bond (a) (b)

Protein Structure and Function A functional protein consists of one or more polypeptides twisted, folded, and coiled into a unique shape Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig A ribbon model of lysozyme (a)(b) A space-filling model of lysozyme Groove

The sequence of amino acids determines a protein’s three-dimensional structure A protein’s structure determines its function Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

What Determines Protein Structure? Remember these things about liver lab In addition to primary structure, physical and chemical conditions can affect structure Alterations in pH, salt concentration, temperature, or other environmental factors can cause a protein to unravel This loss of a protein’s native structure is called denaturation A denatured protein is biologically inactive Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig Normal protein Denatured protein Denaturation Renaturation

Concept 5.5: Nucleic acids store and transmit hereditary information The amino acid sequence of a polypeptide (protein) is determined by chemical information found on segments of DNA (aka: genes) Genes are made of DNA, a nucleic acid Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Roles of Nucleic Acids There are two types of nucleic acids: – Deoxyribonucleic acid (DNA) – Ribonucleic acid (RNA) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Structure of Nucleic Acids Each polynucleotide is made of monomers called nucleotides Each nucleotide consists of a nitrogenous base, a pentose sugar, and a phosphate group Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-27ab 5' end 5'C 3'C 5'C 3'C 3' end (a) Polynucleotide, or nucleic acid (b) Nucleotide Nucleoside Nitrogenous base 3'C 5'C Phosphate group Sugar (pentose)

Fig. 5-27c-1 (c) Nucleoside components: nitrogenous bases Purines Guanine (G) Adenine (A) Cytosine (C) Thymine (T, in DNA)Uracil (U, in RNA) Nitrogenous bases Pyrimidines

Fig. 5-27c-2 Ribose (in RNA)Deoxyribose (in DNA) Sugars (c) Nucleoside components: sugars

Fig. 5-UN5

Fig. 5-UN6