Modified from Kim Foglia OH H HO CH2OH O Carbohydrates Modified from Kim Foglia

Carbohydrates are composed of C, H, O carbo - hydr - ate (CH2O)x C6H12O6 Function: energy u energy storage raw materials u structural materials Monomer: sugars ex: sugars & starches carb = caron hydr = hydrogen ate = oxygen compound

Sugars 6 5 3 Most names for sugars end in -ose Classified by number of carbons 6C = hexose (glucose) 5C = pentose (fructose, ribose) 3C = triose (glyceraldehyde) Glyceraldehyde H OH O C OH H HO CH2OH O Glucose CH2 OH HO O H Fructose CH2OH 6 5 3

What functional groups? carbonyl aldehyde carbonyl ketone

Sugar structure 5C & 6C sugars form rings in aqueous solutions Carbons are numbered

energy stored in C-C bonds Numbered carbons C 6' C O 5' C C 4' 1' energy stored in C-C bonds C C 3' 2'

Simple & complex sugars Monosaccharides simple 1 monomer sugars glucose Disaccharides 2 monomers sucrose Polysaccharides large polymers starch OH H HO CH2OH O Glucose

Building sugars Dehydration synthesis monosaccharides disaccharide | glucose | glucose | maltose maltose glycosidic linkage

Building sugars Dehydration synthesis monosaccharides disaccharide | glucose | fructose | sucrose sucrose = table sugar structural isomers glycosidic linkage

Polysaccharides Polymers of sugars Function: costs little energy to build easily reversible = release energy Function: energy storage starch (plants) glycogen (animals) structure = building materials cellulose (plants) chitin (arthropods & fungi) Polysaccharides are polymers of hundreds to thousands of monosaccharides

Branched vs. linear polysaccharides Can you see the difference between starch & glycogen? Which is easier to digest? Glycogen = many branches = many ends Enzyme can digest at multiple ends. Animals use glycogen for energy storage == want rapid release. Form follows function. APBio/TOPICS/Biochemistry/MoviesAP/05_07Polysaccharides_A.swf

Polysaccharide diversity Molecular structure determines function isomers of glucose how does structure influence function…

Digesting starch vs. cellulose enzyme starch easy to digest Starch = all the glycosidic linkage are on same side = molecule lies flat Cellulose = cross linking between OH (H bonds) = rigid structure enzyme cellulose hard to digest

Cellulose Most abundant organic compound on Earth 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.

Cow can digest cellulose well; no need to eat supplemental sugars Gorilla can’t digest cellulose well; must supplement with sugar source, like fruit 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. APBioTOPICS/20Biochemistry/MoviesAP/Macromolecule-Lifewire.swf

Glycemic index Which food will get into your blood more quickly? apple rice cakes corn flakes bagel peanut M&M

Glycemic index Ranking of carbohydrates based on their immediate effect on blood glucose (blood sugar) levels Carbohydrate foods that breakdown quickly during digestion have the highest glycemic index. Their blood sugar response is fast & high.

Glycemic index Which food will get into your blood more quickly? apple 36 rice cakes 82 corn flakes 84 bagel 72 peanut M&M 33 Why do we find sweet foods pleasurable to eat? Why are we attracted to sweet food?