What is glycogen? How is it different from starch.

The carbohydrates are stored in animal body as glycogen. It is also known as animal starch.
Its structure is similar to amylopectin and is highly branched.
Where as starch consists of two components
1) Amylose, which is linear polymer of $\mathrm{\alpha }$ -Dglucose
2) Amylopectin, which is branched polymer of $\mathrm{\alpha }$ -D-glucose.