1. Carbohydrates Disaccharides Dr. Nikhat Siddiqi1

2. Contents Dr. Nikhat Siddiqi2  Lactose  Maltose  Cellobiose  Sucrose

3. Dr. Nikhat Siddiqi3  Disaccharides are molecules composed of two monosaccharides that are linked by a glycosidic bonds. A glycosidic bond between two hexoses producing a disaccharide

4. Lactose Dr. Nikhat Siddiqi4  Found in milk.  Composed of one galactose linked through the hydroxyl group on carbon 1 in a beta – glycosidc linkage to the hydroxyl group of carbon 4 of a molecule of glucose (  1,4).

5. Maltose Dr. Nikhat Siddiqi5  Also known as malt sugar.  Intermediate product of starch hydrolysis and does not exist free in nature.  Disacharide with  (1,4) glycosidic bond between two glucose residues.

6. Cellobiose Dr. Nikhat Siddiqi6  Degradation product of cellulose, contains two molecules of glucose linked by  (1,4) glycosidic bond.

7. Sucrose Dr. Nikhat Siddiqi7  Table sugar.  Transportable source of energy in plants.  Contains both  -D-glucose and  -D-fructose residues.  The two monosaccharides are linked through glycosidic bond btween both anomeric carbons.  Neither ring can revert to open-chain form, it is non reducing sugar.

8. Sucrose Dr. Nikhat Siddiqi8

9. Sucrose Dr. Nikhat Siddiqi9  Sucrose is not a reducing because both anomeric groups are involved in glycosidic linkage.

10. Dr. Nikhat Siddiqi10