Question

What is glycogen? How is it different from starch?

Answer 1

Glycogen is a carbohydrate (polysaccharide). In animals, carbohydrates are stored as glycogen.

Starch is a carbohydrate consisting of two components − amylose (15 − 20%) and amylopectin (80 − 85%).

However, glycogen consists of only one component whose structure is similar to amylopectin. Also, glycogen is more branched than amylopectin.

Answer 2

Glycogen is a condensation polymer of α-D glucose. Starch is not a single compound but is a mixture of two components—a water soluble component called amyldse (15 – 20%) and water insoluble component called amylopectin (80 – 85%). Amylose is a linear polymer of α-D-glucose. But both glycogen and amylopectin are branched polymers of α-D-glucose; further, glycogen is more highly branched than amylopectin, as amylopectin chains consist of 20 – 25 glucose units, while glycogen chains consist of 10 – 14 glucose units.