What is glycogen? How is it different from starch?

Explanation

Glycogen is a branched polymor of `alpha`-D-glucose. Just as glucose is stored in plants as starch, it (glucose) is stored as glycogen in the liver and muscles of human beings. When the body needs glucose during fasting or hard work, glycogen undegoes hyrolysis by the action of enzymes to provide glucose. However, starch is not a single compound, but is a mixture of two components: (i) a water-soluble component and (ii) a water-insoluble component called amylopectin( a branched polymer of `alpha`-D-glucose). Glycogen differ from amylopectin in that the former is more highly branced polymer of `alpha`-D-glucose.