OH H HO CH2OH O Carbohydrates energy molecules 2006-2007

Carbohydrates

Carbohydrates are composed of C, H, O carbo - hydr - ate sugar Carbohydrates Carbohydrates are composed of C, H, O carbo - hydr - ate General formula: CH2O (CH2O)x C6H12O6 Function: energy u energy storage raw materials u structural materials Monomer (building block): sugars ex: sugars, starches, cellulose carb = carbon 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 (ribose) 3C = triose (glyceraldehyde) Glyceraldehyde H OH O C OH H HO CH2OH O Glucose H OH HO O Ribose CH2OH 6 5 3

Where do you find solutions? Sugar structure 5C & 6C sugars form rings in solution Where do you find solutions? In cells! 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 OH H HO CH2OH O Glucose Monosaccharides simple 1 monomer sugars glucose Disaccharides 2 monomers sucrose Polysaccharides large polymers starch

Dehydration Synthesis= Polymerization Anabolic reaction Produces polymer Monomer + Monomer  Polymer + Water 2 Monomers Bond= Polymer Remove H2O 8

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

Let’s go to the videotape! Building sugars Synthesis monosaccharides disaccharide | glucose | fructose | sucrose (table sugar) sucrose = table sugar Let’s go to the videotape!

Separate polymer into: Hydrolysis Catabolic reaction Produces monomers Ex) Polysaccharides monosaccharides Polymer + Water  Monomer + Monomer Separate polymer into: 2 monomers Add H2O 11

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

Linear vs. branched polysaccharides starch (plant) What does branching do? energy storage 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 glycogen (animal) Let’s go to the videotape!

Polysaccharide diversity Molecular structure determines function in starch in cellulose isomers of glucose structure determines function…

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

BIG DEAL! Who can live on this stuff?! Cellulose Most abundant organic compound on Earth herbivores can digest cellulose most carnivores cannot digest cellulose that’s why they eat meat to get their energy & nutrients cellulose = roughage 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. BIG DEAL! Who can live on this stuff?!

Cow Gorilla can digest cellulose well; no need to eat other sugars can’t digest cellulose well; must add another sugar source, like fruit to diet 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

Helpful bacteria How can cows digest cellulose? bacteria live in their gut & help digest cellulose-rich (grass) meals