Macromolecules 4 major classes of macromolecules: carbohydrates lipids proteins nucleic acids

–monomers building blocks repeated small units –polymers Molecules consisting of 2 or more monomers Dehydration synthesis / Condensation

H2OH2O HO H HH 3 Polymer Formation (synthesis) -joins monomers by “taking” H 2 O out one monomer donates OH – other monomer donates H + together these form H 2 O requires energy & enzymes enzyme Dehydration synthesis / Condensation

H2OH2O HOH H H 4 Polymer Breakdown (digestion) –use H 2 O to breakdown polymers reverse of dehydration synthesis cleave off one monomer at a time H 2 O is split into H + and OH – –H + & OH – attach to ends –requires enzymes –releases energy enzyme Hydrolysis

Carbohydrates -Composed of C, H, O carbo-hydrate CH 2 O C 6 H 12 O 6  Most names for sugars end in -ose  Classified by number of carbons  6C = hexose (glucose)  5C = pentose (ribose)  3C = triose (glyceraldehyde) *5C & 6C sugars form rings in solution

Types of Carbohydrates 6 Monosaccharides –1 simple sugar (monomers) –glucose, galactose, fructose Disaccharides –2 monosaccharides –sucrose, maltose, lactose Polysaccharides –3 or more monosaccharides (polymers) –starch, cellulose, chitin, glycogen OH H H HO CH 2 OH H H H OH O Glucose

7 glucose glucose maltose 1,4 glycosidic linkage *Position of linkage determines function glucose fructose sucrose 1,2 glycosidic linkage

8 Polysaccharides  Polymers of sugars  Function:  energy storage  starch (plants)  glycogen (animals)  structure = building materials  cellulose (plants)  chitin (arthropods & fungi)

9 Unbranched vs Branched starch (plant) glycogen (animal) p62 Fig 5.6

10 Structural Polysaccharides Cellulose makes up plant cell walls and differs from starch by glycosidic linkages p63 Fig 5.7 starch cellulose *isomers of glucose alpha = below plane....allbeta = above plane....every other

11 Digesting starch vs. cellulose cellulose hard to digest starch easy to digest

12 Structure Cellulose -straight -chains...H-bonds Starch -helical ml