BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The correct answer is a) humans have enzymes that can hydrolyze the a-glycosidic linkages of starch but not the B-glycosidic linkages of cellulose. The human body uses enzymes called alpha-amylases to break down the alpha-glycosidic linkages of starch but they cannot break down beta-glycosidic linkages.

Detailed explanation-2: -The most important difference in the way the two polymers behave is this: You can eat starch, but you can’t digest cellulose. Your body contains enzymes that break starch down into glucose to fuel your body. But we humans don’t have enzymes that can break down cellulose.

Detailed explanation-3: -The glycosidic linkages in cellulose can’t be broken by human digestive enzymes, so humans are not able to digest cellulose.

Detailed explanation-4: -Humans lack digestive enzymes capable of hydrolyzing (breaking apart) most -glycosidic bonds, which explains why amylose, a glucose polymer with -1, 4 glycosidic bonds, is digestible by human enzymes, while cellulose, a glucose polymer with -1, 4 glycosidic bonds, is indigestible (Figure 1).

Detailed explanation-5: -Humans are only capable of digesting alpha linked glucose polymers, and are unable to break down beta linked polymers. As a result, cellulose is incapable of being broken down by humans. Starch is formed by an-1, 4 linkage, while glycogen is formed by an-1, 6 linkage.