1. Carbohydrates

2. Carbohydrates Composed of carbon, hydrogen, oxygen
General formula Cx(H2O)y
Two types: simple sugars and condensation polymers
Functions:
Energy
Precursors for metabolic rxns
Storage
Structural material (plants)

3. Monosaccharides Simple sugars Soluble in water (glucose, fructose)
Classified by number of carbons
Contain two or more hydroxyl groups and one carbonyl group
Exist in chain or ring form
Hydroxyl group in ring form can be either α (projected downward) or β (projected upward)

4. +
D-fructose
α-D-fructose
β-D-fructose

5. Disaccharides Two simple sugars linked together
Soluble in water, hydrolysed by acid hydrolysis or enzymes
Condensation reaction!
Resulting bond: glycosidic link (1-4 link b/c C1 bonded to C4)
Lactose: beta-glucose + beta-galatose
Maltose: alpha-glucose + alpha-glucose
Sucrose: alpha-glucose + beta-fructose

7. Polysaccharides
Long chains of monosaccharide units held together by glycosidic bonds
Insoluble in water, ideal for storage
3 common polysaccharides
Starch (alpha-glucose), contains amylose and amylopectin, storage carbohydrate in plants (potato, rice, flour)
Glycogen (alpha-glucose), animal starch, found in liver, muscles
Cellulose (beta-glucose), structural material in plants

8. amylose
amylopectin
glycogen
cellulose

9. Starch vs. Cellulose Polymers of glucose
Starch: alpha-glycosidic links
Cellulose: beta-glycosidic links
Different linkage forms uncoiled linear structure w/ alternating glucose monomers: hydroxyl groups form H bonds with hydroxyl of other parallel cellulose
Cannot digest cellulose b/c enzyme cellulase not produced in humans and most mammals

10. Dietary Fiber! Plant material
Cellulose, pectin, waxes, lignin
Cannot hydrolyze b/c lack cellulase enzyme
Why is it important?
Prevention!
Irritable bowel syndrome
Constipation
Hemorrhoids
Colorectal cancer