Carbohydrates

OH H HO CH2OH O Carbohydrates: Energy molecules 2006-2007

sugar - sugar - sugar - sugar - sugar Carbohydrates Building block molecules = sugars sugar - sugar - sugar - sugar - sugar sugar

Carbohydrates Function: Example quick energy energy storage structure sugars starches cellulose (cell wall) glucose C6H12O6 sucrose starch

Sugars = building blocks Names for sugars usually end in glucose fructose sucrose maltose -ose OH H HO CH2OH O glucose C6H12O6 fructose maltose sucrose

Building carbohydrates Synthesis 2 sugars = disaccharide monosaccharides | glucose | glucose | maltose

Building carbohydrates Synthesis 2 sugars = disaccharide monosaccharides | glucose | fructose | sucrose (table sugar)

BIG carbohydrates Starch Glycogen Cellulose Chitin energy storage in plants potatoes Glycogen energy storage in animals in liver & muscles Cellulose structure in plants cell walls Chitin structure in arthropods & fungi exoskeleton

Building BIG carbohydrates glucose + glucose + glucose… = polysaccharide starch (plant) energy storage glycogen (animal)

Too Much Energy Storage!

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

Cellulose Cell walls in plants 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 or a horse (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 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

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