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Transcript
Chapter 5. Macromolecules AP Biology 2005-2006 Macromolecules Smaller organic molecules join together to form larger molecules macromolecules 4 major classes of macromolecules: carbohydrates lipids proteins nucleic acids AP Biology 2005-2006 Polymers Long molecules built by linking chain of repeating smaller units polymers monomers = repeated small units covalent bonds AP Biology 2005-2006 How to build a polymer Condensation reaction dehydration synthesis joins monomers by “taking” H2O out 1 monomer provides OH the other monomer provides H together these form H2O AP Biology requires energy & enzymes 2005-2006 How to break down a polymer Hydrolysis use H2O to break apart monomers reverse of condensation reaction H2O is split into H and OH H & OH group attach where the covalent bond used to be AP Biology ex: digestion is hydrolysis 2005-2006 Carbohydrates AP Biology 2005-2006 Carbohydrates Carbohydrates are composed of C, H, O carbo - hydr - ate CH2O (CH2O)x C6H12O6 Function: energy raw materials materials energy storage structural Monomer: sugars ex: sugars & starches AP Biology 2005-2006 Sugars Most names for sugars end in -ose Classified by number of carbons 6C = hexose (glucose) 5C = pentose (fructose, ribose) 3C = triose (glyceraldehyde) AP Biology 2005-2006 Simple & complex sugars Monosaccharides simple 1 monomer sugars glucose Disaccharides 2 monomers sucrose Polysaccharides large polymers starch AP Biology 2005-2006 Building sugars Dehydration synthesis monosaccharides | glucose | glucose disaccharide | maltose glycosidic linkage AP Biology 2005-2006 Polysaccharides Polymers of sugars costs little energy to build easily reversible = release energy Function: energy storage starch (plants) glycogen (animals) building materials = structure cellulose (plants) chitin (arthropods & fungi) AP Biology 2005-2006 Polysaccharide diversity Molecular structure determines function isomers of glucose How does structure influence function… AP Biology 2005-2006 Digesting starch vs. cellulose AP Biology 2005-2006 Cow can digest cellulose well; no need to eat supplemental sugars Gorilla can’t digest cellulose well; must supplement with sugar source, like fruit AP Biology 2005-2006 Glycemic index Which food will get into your blood more quickly? AP Biology apple rice cakes corn flakes bagel peanut M&M 2005-2006 Glycemic index Which food will get into your blood more quickly? AP Biology apple rice cakes corn flakes bagel peanut M&M 36 82 84 72 33 2005-2006 Lipids AP Biology 2005-2006 Lipids Lipids are composed of C, H, O long hydrocarbon chain Diverse group fats phospholipids steroids Do not form polymers big molecules made of subunit smaller molecules not a continuing chain AP Biology 2005-2006 Fats Structure: glycerol (3C alcohol) + fatty acid fatty acid = long HC “tail” with COOH group at “head” dehydration synthesis AP Biology 2005-2006 Fat Triacylglycerol 3 fatty acids linked to glycerol ester linkage = between OH & COOH AP Biology 2005-2006 Dehydration synthesis AP Biology 2005-2006 Fats Long HC chain polar or non-polar? hydrophilic or hydrophobic? Function: energy storage very rich 2x carbohydrates cushion organs insulates body think whale blubber! “Let’s go to the video tape!” AP Biology (play movie here) 2005-2006 Saturated fats All C bonded to H No C=C double bonds long, straight chain most animal fats solid at room temp. contributes to cardiovascular disease (atherosclerosis) = plaque deposits AP Biology 2005-2006 Unsaturated fats C=C double bonds in the fatty acids plant & fish fats vegetable oils liquid at room temperature the kinks made by double bonded C prevent the molecules from packing tightly together AP Biology 2005-2006 Cholesterol Important cell component animal cell membranes precursor of all other steroids including vertebrate sex hormones AP Biology high levels in blood may contribute to cardiovascular disease 2005-2006 Proteins AP Biology 2005-2006 Proteins Most structurally & functionally diverse group of biomolecules Function: involved in almost everything AP Biology enzymes structure (keratin, collagen) carriers & transport (membrane channels) receptors & binding (defense) contraction (actin & myosin) signaling (hormones) storage (bean seed proteins) 2005-2006 Proteins Structure: monomer = amino acids 20 different amino acids polymer = polypeptide protein can be 1 or more polypeptide chains folded & bonded together large & complex molecules complex 3-D shape AP Biology 2005-2006 Amino acids Structure: central carbon amino group carboxyl group (acid) R group (side chain) variable group confers unique chemical properties of the amino acid AP Biology H O H | || —N— —C— C—OH | H R 2005-2006 Nonpolar amino acids nonpolar & hydrophobic Why are these nonpolar & hydrophobic? AP Biology 2005-2006 Polar amino acids polar or charged & hydrophilic AP Biology Why are these polar & hydrophillic? 2005-2006 Building proteins Peptide bonds: dehydration synthesis linking NH2 of 1 amino acid to COOH of another C–N bond AP Biology peptide bond 2005-2006 Building proteins Polypeptide chains N-terminal = NH2 end C-terminal = COOH end repeated sequence (N-C-C) is the polypeptide backbone grow in one direction AP Biology 2005-2006 Protein structure & function function depends on structure 3-D structure twisted, folded, coiled into unique shape pepsin hemoglobin AP Biology 2005-2006 collagen Protein structure & function function depends on structure all starts with the order of amino acids what determines that order of amino acids? lysozyme: enzyme in tears & mucus that kills bacteria “Let’s go to the video tape!” AP Biology (play movie here) the 10 glycolytic enzymes used to breakdown glucose 2005-2006 to make ATP Primary (1°) structure Order of amino acids in chain amino acid sequence determined by DNA slight change in amino acid sequence can affect protein’s structure & it’s function even just one amino acid change can make all the difference! AP Biology 2005-2006 Sickle cell anemia “Let’s go to the video tape!” AP Biology (play movie here) 2005-2006 Denature a protein Disrupt 3° structure pH salt temperature unravel or denature protein disrupts H bonds, ionic bonds & disulfide bridges Some proteins can return to their functional shape after denaturation, many cannot AP Biology 2005-2006 Any Questions?? AP Biology 2005-2006