What is glycogen? How is it different from starch?

Explanation

Starch is not a single compound but is a mixture of two compents - a waterf soluble component called amylose `(15-20%)` and water insoluble component called amylopectin `(80-85%)` . Amylose is a linear polymer of `alpha`-D-glucose. But both glycogen and amylopectin are branched polymers of `alpha`-D-glucose, rather glycogen is more highly branched than amylopectin. Whereas amylopectin chains consist of `20-25` glucose units, glycogen chains consist of `10-14` glucose units.