Final answer:
Glycogen is a highly branched polysaccharide of glucose that serves as the energy storage molecule in animals. It is made and stored primarily in the liver and muscles.
Step-by-step explanation:
Glycogen is a highly branched polysaccharide of glucose monomers that serves as the energy storage molecule in animals. It is primarily made and stored in the cells of the liver and muscles. Glycogen contains up to 106 D-glucose units joined by α-1,4-glycosidic linkages and branching through α-1,6-glycosidic linkages. The main difference between glycogen and starch is that glycogen has more frequent branching at 10 to 15 glucose units interval, making it more soluble in water and easier to break down when the body needs glucose.