1. Carbohydrates
Section 3.2

2. Learning Objectives
Explain the difference between monosaccharides, disaccharides, & polysaccharides
Give examples of monosaccharides, disaccharides, & polysaccharides
Compare storage polysaccharides with structural polysaccharides

3. Carbohydrate Basics
Carbohydrate = Compound made up of C, H, & O in the ratio of 1C:2H:1O
Example: C6H12O6
Names usually end in -ose
Monomer units are monosaccharides (simple sugars)
Examples: glucose, fructose, & galactose
Glucose is the most abundant
Main function is to serve as an energy source

4. (Don’t copy!) Glucose and Fructose are Structural Isomers!
Aldehyde – C=O bond is on an end carbon atom
Ketone – C=O bond is on an interior carbon atom

5. Monosaccharides in Solution
Many monosaccharides form rings in aqueous solution (water)
Ring diagrams may be abbreviated by not showing the carbons at the corners

6. Disaccharides
Disaccharides = 2 monosaccharides connected by a glycosidic linkage
Monomers joined by a condensation reaction
Are a nutritional source of monosaccharides
Examples: sucrose, lactose, & maltose
Glucose ➞
← Fructose
Sucrose

8. Polysaccharides Polysaccharides —long chains of simple sugars
Function is energy storage and structural support
Examples include:
Starch —glucose storage in plants
Glycogen —glucose storage in animals
Cellulose —tough fibers that give plants strength and rigidity
Chitin – tough polymer found in cell walls of fungi (mushrooms) & exoskeletons of arthropods (ex. crustaceans & insects)

10. Digesting Cellulose
Animals do not have an enzyme that can break down cellulose
Can’t hydrolyze cellulose
There are some bacteria species that can digest cellulose
Live in the digestive system of termites, cows, and sheep

11. Other Carbohydrates Glycoproteins = carbohydrate bonded to a protein
Found in the cell membrane of cells
Allow cells to stick to each other or provides protection
Glycolipids = carbohydrate bonded to a lipid molecule
Allow cells to recognize & interact with each other