1. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 1 Chapter 16 Carbohydrates 16.7 Disaccharides 16.8 Polysaccharides

2. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 2 Disaccharides A disaccharide consists of two monosaccharides. DisaccharideMonosaccharides Maltose + H 2 O Glucose + Glucose Lactose + H 2 OGlucose + Galactose Sucrose + H 2 O Glucose + Fructose

3. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 3 Maltose Maltose is: A disaccharide in which two D-glucose molecules are joined by an  -1,4- glycosidic bond. Obtained from starch. Used in cereals, candies, and brewing.

4. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 4 Lactose Lactose is: Also called milk sugar. Composed of galactose and glucose linked by a  -1,4-glycosidic bond.

5. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 5 Sucrose Sucrose: Is the disaccharide known as table sugar. Is composed of glucose and fructose molecules joined by ,  -1,2- glycosidic bond. Has no isomers because mutarotation is blocked.

6. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 6 Sweetness of Sweeteners Sugars and artificial sweeteners differ in sweetness. Each sweetener is compared to sucrose (table sugar), which is assigned a value of 100.

7. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 7 Identify the monosaccharides in each as 1) glucose, 2) fructose 3) galactose. A. Lactose B. Maltose C. Sucrose Learning Check

8. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 8 Identify the monosaccharides in each as 1) glucose, 2) fructose 3) galactose. A. Lactose 1) glucose, 3) galactose B. Maltose 1) glucose, 1) glucose C. Sucrose1) glucose, 2) fructose Solution

9. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 9 Polysaccharides Polysaccharides are polymers of D-glucose Important polysaccharides are: Starch (Amylose and Amylopectin) Glycogen Cellulose D-Glucose

10. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 10 Amylose, Amylopectin, and Glycogen Amylose is a continuous chain of glucose molecules linked by  -1,4 glycosidic bonds. Amylopectin is a branched chain of glucose molecules linked by  -1,4- and  -1,6- glycosidic bonds. Glycogen is similar to amylopectin, but more highly branched.

11. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 11 Structures of Amylose and Amylopectin

12. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 12 Cellulose Cellulose is a polymer of glucose molecules linked by  -1,4 glycosidic bonds. Enzymes in saliva can hydrolyze  -1,4 glycosidic bonds in starch, but not  -1,4 glycosidic bonds in cellulose.

13. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 13 Identify the types of glycosidic bonds in: 1) Amylose 2) Glycogen 3) Cellulose Learning Check

14. Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 14 Identify the types of glycosidic bonds in 1) Amylose  -1,4 glycosidic bonds 2) Glycogen  -1,4- and  -1,6-glycosidic bonds 3) Cellulose  -1,4 glycosidic bonds Solution