Question

What is glycogen? How it is different from Starch?

Answer 1

Glycogen is a branched polymer of Glucose. Glucose units are linked by $\alpha$ (1,4) glycosidic bond.

Both starch and glycogen are biopolymers of glucose residue. The difference between them is that Glycogen is extensively branched polymer and starch is found in linear chain polymer ($Amylose$) as well as in branched form ($Amylopectin$) but not as it is branched in Glycogen as shown in the figure.