1. Carbohydrates most abundant organic molecules in nature Lecture 15. Carbohydrates1 Lecture 14. Subunit Interactions and Quaternary Structure 1 Lecture 1. Introduction to Biochemistry 1

2. IMPORTANCE Photosynthesis stores energy in carbohydrates; Carbohydrates are the metabolic precursors of all other biomolecules; Important component of cell structures; Important function in cell-cell recognition;

3. 3 Carbohydrate Classes Monosaccharide Simple sugars, can not be broken down further; general formula (CH 2 O)n Examples

4. Alpha vs Beta glucose

5. Can be Aldoses Contain aldehyde Ketoses Contain ketones

6. Disaccharide - two sugars formed by dehydration synthesis

7. glucose + fructose  sucrose + water table sugar glucose +galactose  lactose + water milk sugar glucose + glucose  maltose + water malt sugar

8. Carbohydrate Classes Disaccharides Simplest oligosaccharides; Contain two monosaccharides linked by a glycosidic bond; Lecture 15. Carbohydrates8

9. Oligiosaccharide short chain 3 -10 monomers long Identification on cells

10. Carbohydrate Classes Polysaccharides Polymers of monosaccharides

11. Polysacchrides Starch and glycogen are storage molecules; Chitin and cellulose are structural molecules; Cell surface polysaccharides are recognition molecules. Lecture 15. Carbohydrates11

12. Polysacchrides Glucose is the monosaccharides of the following polysacchrides with different linkages and banches  (1,4), starch (more branch)  (1,4), glycogen (less branch)  (1,4), cellulose (cell walls of all plants)  (1,4), Chitin similar to cellulose, but C2-OH is replaced by –NHCOCH 3 (found in exoskeletons of crustaceans, insects, spiders) Lecture 15. Carbohydrates12

13. Carbohydrates Polysaccharide - glycogen many glucose units in a branching pattern liver and skeletal muscle are good sources hormone insulin stimulates glycogen production (glycogenesis) hormone glucagon stimulates glycogen breakdown (glycogenolysis) glycogen is found in animal cells as an inclusion

14. Carbohydrates Starches are complex carbohydrates, often two polysaccharide chains plants make starches, including the indigestible cellulose examples - wheat, rice, corn, potato, cassava, rye, barley