AP Biology Macromolecules

AP Biology Macromolecules  Smaller organic molecules join together to form larger molecules Macromolecules  4 major classes of macromolecules Carbohydrates Lipids Proteins Nucleic acids

AP Biology Polymers  Long molecules built by linking chain of repeating smaller units Polymers Monomers = repeated small units Covalent bonds

Fig. 5-2a Dehydration removes a water molecule, forming a new bond Short polymerUnlinked monomer Longer polymer Dehydration reaction in the synthesis of a polymer HO H2OH2O H H H (a)

AP Biology How to build a polymer  Condensation reaction Dehydration synthesis Joins monomers by “taking” water out 1 monomer provides OH Other monomer provides H Together they form water Requires energy and enzymes

Fig. 5-2b Hydrolysis adds a water molecule, breaking a bond Hydrolysis of a polymer HO H2OH2O H H H (b)

AP Biology How to break down a polymer  Hydrolysis Use water to break apart monomers Reverse of condensation reaction Water is split into H and OH H and OH group attach where the covalent bond used to be Example: digestion is hydrolysis

AP Biology Carbohydrates

AP Biology Carbohydrates  Composed of C,H,O Carbo –hydr --ate CH 2 O (CH 2 )x C 6 H 12 O 6  Function Energy Raw materials Energy storage Structural materials  Monomer: sugars  Example: sugars and starches

AP Biology Sugars  Most names for sugars end in –ose  Classified by number of carbons 6C = hexose (glucose) 5C = pentose (fructose, ribose) 3C = triose (glyceraldehyde)

Dihydroxyacetone Ribulose Ketoses Aldoses Fructose Glyceraldehyde Ribose Glucose Galactose Hexoses (C 6 H 12 O 6 ) Pentoses (C 5 H 10 O 5 ) Trioses (C 3 H 6 O 3 ) Functional Groups?

AP Biology Sugar structure  5C and 6C sugars form rings in aqueous solutions In cells!

AP Biology Numbered carbons

AP Biology Simple and complex sugars  Monosaccharides Simple 1 monomer sugars Glucose  Disaccharides 2 monomers Sucrose  Polysaccharides Large polymers starch

AP Biology Building sugars  Dehydration synthesis

AP Biology Building sugars  Dehydration synthesis

AP Biology 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 and fungi)

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

AP Biology Polysaccharide diversity  Molecular structure determines function Isomers of glucose How does structure influence function….  Glucose  Glucose

AP Biology Digesting starch vs. cellulose (b) Starch: 1–4 linkage of  glucose monomers (c) Cellulose: 1–4 linkage of  glucose monomers

Fig. 5-9

 Glucose monomer Cellulose molecules Microfibril Cellulose microfibrils in a plant cell wall 0.5 µm 10 µm Cell walls Cellulose is most abundant organic compound on earth

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.