Carbohydrates

Sugars make rings in aqueous solutions H When sugars bond together, it happens at the 1 and 4 carbons. OH H C 6' C O 5' H H H C C 4' 1' OH OH OH H C C 3' 2' H OH

Simple & complex sugars OH H HO CH2OH O Glucose Simple & complex sugars Monosaccharides simple 1 monomer sugars Ex. glucose, fructose Disaccharides 2 monomers Ex. maltose, sucrose Polysaccharides large polymers Starch, cellulose, chitin, glycogen

Polysaccharides Polymers of sugars Function: energy storage structure glucose glucose glucose glucose glucose glucose glucose glucose Polysaccharides Polymers of sugars Function: energy storage starch (plants) glycogen (animals) in liver & muscles structure cellulose (plants) chitin (arthropods & fungi) Polysaccharides are polymers of hundreds to thousands of monosaccharides

Building bigger sugars Dehydration synthesis monosaccharides disaccharide H2O | glucose | fructose | sucrose (table sugar) sucrose = table sugar

Digesting polysaccharides Say you ate a potato (full of starch!). What kind of reaction will your body carry out to digest the starch (we’ll say, 200 glucose bonded together) into monomers? What are the reactants? What are the products? Challenge: balance the equation! Cross-linking between polysaccharide chains: = rigid & hard to digest The digestion of cellulose governs the life strategy of herbivores. Either you do it really well and you’re a cow or an elephant (spend a long time digesting a lot of food with a little help from some microbes & have to walk around slowly for a long time carrying a lot of food in your stomach) Or you do it inefficiently and have to supplement your diet with simple sugars, like fruit and nectar, and you’re a gorilla. C1200H2002O1001+ 199H2O--> 200C6H12O6

Metabolism Sum of all reactions in your body When you eat disachharides or polysaccharides, what happens? When you have too much glucose in your blood, what happens?