C ARBOHYDRATES SC.912.L.18.2

E SSENTIAL Q UESTION What are carbohydrates made of? How do carbohydrates help living things?

C ARBOHYDRATES Carbohydrates can be monomer like glucose and fructose on the left, or polymers like sucrose on the right. Major source of food energy for many organisms.

C ARBOHYDRATE F UNCTIONS Storage Animals -- as glycogen in the liver Plants -- as starch Structure Cellulose – gives plants strength and rigidity. Major component of wood and paper. Sustenance Human digestive system begins digesting starch in the mouth. Cellulose is referred to as fiber. Humans cannot digest it but it essential for proper nutrition.

M ONOSACCHARIDES Monosaccharides are also called simple sugars. The three most common are Glucose – often called blood sugar Galactose – sugar in milk Fructose – found in honey They all have the formula C 6 H 12 O 6 SASCarbo.htm

D ISACCHARIDES Disaccharides are formed from monosaccharides through dehydration synthesis. Dehydration think loss of water. Lactose and Sucrose are common disaccharides. Lactose – milk Sucrose – fruits and vegetables

P OLYSACCHARIDES Starch, Cellulose and Glycogen are common polysaccharides. Starch and cellulose are formed from long chains of glucose. Glycogen is formed from branching chains of glucose.