Chapter 5 The Structure and Function of Macromolecules PowerPoint Lectures for Biology Seventh Edition Neil Campbell and Jane Reece The Synthesis and Breakdown of Polymers Monomers form larger molecules by condensation reactions called dehydration reactions HO 1 3 2 H Unlinked monomer Short polymer Dehydration removes a water molecule forming a new bond HO Figure 5 2A 1 2 H HO 3 H2O 4 H Longer polymer a Dehydration reaction in the synthesis of a polymer Polymers can disassemble by Hydrolysis HO 1 2 3 4 Hydrolysis adds a water molecule breaking a bond HO 1 2 3 H Figure 5 2B b Hydrolysis of a polymer H H2O HO H Examples of monosaccharides Triose sugars Pentose sugars C3H6O3 C5H10O5 H O H Aldoses C O Hexose sugars C6H12O6 H C H O C H C OH H C OH H C OH H C OH H C OH HO C H C OH H H C OH H Glyceraldehyde H Ribose H C OH H HO C H C OH HO C H H C OH H C OH H C OH H C OH H H Glucose H H Ketoses C Figure 5 3 H C OH H C O Galactose H C OH H C OH C O O C OH H C OH HO H H C OH H C OH Dihydroxyacetone H C OH H C OH H H C OH H Ribulose O C C H H Fructose Monosaccharides May be linear Can form rings O H 1C H 2 HO 3 H H H C C 4 C 5 C 6 C CH2OH 6 OH H OH OH OH 5C H 4 OH 3 C H H O 5 H H OH C CH2OH 6 C C 2 C OH O OH 3 C H CH2OH O H OH 4 1 H H C H 1 H C 2 OH 6 H C OH 4 HO O 5 H OH 3 H H 1 OH 2 OH H Figure 5 4 a Linear and ring forms Chemical equilibrium between the linear and ring structures greatly favors the formation of rings To form the glucose ring carbon 1 bonds to the oxygen attached to carbon 5 Examples of disaccharides a Dehydration reaction in the synthesis of maltose The bonding of two glucose units forms maltose The glycosidic link joins the number 1 carbon of one glucose to the number 4 carbon of the second glucose Joining the glucose monomers in a different way would result in a different disaccharide CH2OH CH2OH H HO O H OH H H H H OH HO H OH H OH H H OHOH H HO H O H H OH H2O H b Dehydration reaction H in the synthesis of O sucrose Sucrose is a disaccharide formed from glucose and fructose Notice that fructose though a hexose like glucose forms a five sided ring H O H H O H O H Glucose O H CH2OH H 1 4 1 glycosidic linkage CH2OH H O H HO HO OH H H H OH H CH2OH H HO H O H O H OH H 1 2 glycosidic 1 linkage H O OH CH2OH O 2 H Sucrose H HO CH2OH OH H H2O Fructose O H O H Maltose H H 4 OH CH2OH O H O Glucose Glucose CH2OH Figure 5 5 O CH2OH Fig 5 6 Chloroplast Mitochondria Glycogen granules Starch 0 5 m 1 m Glycogen Amylose Amylopectin a Starch a plant polysaccharide b Glycogen an animal polysaccharide Structural Polysaccharides Cellulose Fig 5 8 Cellulose Cell walls Cellulose microfibrils in a plant cell wall Microfibril 10 m 0 5 m Cellulose molecules b Glucose monomer Cellulose is difficult to digest Structural Polysaccharides Chitin Chitin another important structural polysaccharide Is found in the exoskeleton of arthropods and cell walls of many fungi CH2O HO OH H H OH H OH H H NH C O CH3 a The structure of the b Chitin forms the exoskeleton of arthropods This cicada chitin monomer is molting shedding its old exoskeleton and emerging Figure 5 10 A C in adult form c Chitin is used to make a strong and flexible surgical thread that decomposes after the wound or incision heals Fig 5 11 Fatty acid palmitic acid Glycerol a Dehydration reaction in the synthesis of a fat Ester linkage b Fat molecule triacylglycerol Saturated fatty acids Have the maximum number of hydrogen atoms possible Have no double bonds Stearic acid Figure 5 12 a Saturated fat and fatty acid Unsaturated fatty acids Have one or more double bonds Oleic acid Figure 5 12 b Unsaturated fat and fatty acid cis double bond causes bending Phospholipid structure Figure 5 13 N CH CH2 3 3 CH2 O O P O Choline Phosphate O CH2 CH O O C O C CH2 Glycerol O Hydrophobic tails Hydrophilic head Consists of a hydrophilic head and hydrophobic tails a Structural formula Fatty acids Hydrophilic head Hydrophobic tails b Space filling model c Phospholipid symbol Fig 5 14 Hydrophilic head Hydrophobic tail WATER WATER Steroids Cholesterol an important steroid is a component in animal cell membranes H3C CH3 CH3 CH3 CH3 Cholesterol HO An overview of protein functions Enzymes Are a type of protein that acts as a catalyst speeding up chemical reactions 1 Active site is available for a molecule of substrate the reactant on which the enzyme acts Substrate sucrose 2 Substrate binds to enzyme Glucose OH Enzyme sucrase H2O Fructose H O 4 Products are released Figure 5 16 3 Substrate is converted to products Amino Acids 20 different amino acids make up proteins CH3 CH3 H H3N C CH3 O H3N C H Glycine Gly O C H3N C H Alanine Ala O C CH2 O H3N C H Valine Val CH2 CH CH3 CH3 O CH3 CH3 O C H3C O H3N C H Leucine Leu O CH C O C H Isoleucine Ile O Nonpolar CH3 CH2 S NH CH2 CH2 H3N C H O H3N C O Methionine Met Figure 5 17 CH2 C H CH2 O H3N C O Phenylalanine Phe C H O H2C CH2 H2N C O C H C O Tryptophan Trp Proline Pro O Amino Acids OH OH Polar CH2 H3N C CH O H3N C C O H Serine Ser CH2 O H3N C O H C CH2 O C H H3N C O CH2 O H3N C O Electrically charged H3N O NH3 O CH2 C CH2 CH2 CH2 CH2 CH2 CH2 CH2 O C H3N C O CH2 C H O H3N C H Aspartic acid Asp O C O C O H Glutamine Gln NH2 C H H3N C Asparagine Asn C O CH2 Basic O C CH2 O H Acidic C O H Tyrosine Tyr Cysteine Cys Threonine Thr C NH2 O C SH CH3 OH NH2 O Glutamic acid Glu NH2 C Lysine Lys H3N C H C H CH2 NH CH2 H3N CH2 O O NH O C O O C O Arginine Arg Histidine His Amino Acid Polymers Amino acids are linked by peptide bonds Peptide bond OH CH2 H N H SH …
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