Glycogen is a complex polysaccharide. It is composed of numerous α-glucose molecules. In the process of glycogenesis, 30,000 molecules of glucose combine to form glycogen. Glucose molecules are linked by α-1-4 glycosidic bonds to form glycogen. Branching of glycogen occurs through α-1-6 linkage. Each branch contains 10-20 glucose molecules. Their molecular weight is 106-107 daltons. Glycogen is hydrolyzed into glucose. Glycogen is converted to glucose when needed to provide carbon and energy. For this reason, glycogen is called animal starch.