1. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.1 Chapter 15 Carbohydrates 15.5 Disaccharides

2. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.2 Important Disaccharides A disaccharide  consists of two monosaccharides Monosaccharides Disaccharide Glucose + glucose maltose + H 2 O Glucose + galactoselactose + H 2 O Glucose + fructosesucrose + H 2 O

3. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.3 Maltose Maltose is  a disaccharide also known as malt sugar  composed of two D -glucose molecules  obtained from the hydrolysis of starch  linked by an  -1,4-glycosidic bond between the  —OH on C1 of the first glucose and —OH on C4 of the second glucose  used in cereals, candies, and brewing  found in both the  - and  - forms

4. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.4 Formation of Maltose

5. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.5 Lactose  is a disaccharide of  - D -galactose and  - or  - D - glucose  contains a  -1,4-glycosidic bond  is found in milk and milk products  is found in both the  - and  - forms

6. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.6 Lactose (continued)

7. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.7 Sucrose Sucrose, or table sugar,  is obtained from sugar cane and sugar beets  consists of  - D -glucose and  - D -fructose  has an ,  -1,2-glycosidic bond

8. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.8 Learning Check Draw the Haworth structures and give the names of the two monosaccharides that form when sucrose is hydrolyzed.

9. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.9 Solution

10. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.10 Sweeteners Sugars and artificial sweeteners  differ in sweetness  are compared to sucrose (table sugar), which is assigned a value of 100

11. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.11 Learning Check Identify the monosaccharides in each of the following: A. lactose 1)  - D -glucose 2)  - D -fructose 3)  - D -galactose B. maltose 1)  - D -glucose 2)  -D-fructose 3)  - D -galactose C. sucrose 1)  - D -glucose 2)  - D -fructose3)  - D -galactose

12. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.12 Solution Identify the monosaccharides in each of the following: A. lactose 1)  - D -glucose 3)  - D -galactose B. maltose 1)  - D -glucose C. sucrose 1)  - D -glucose 2)  - D -fructose