How does glycogen act as a source of energy?

Glycogen is an energy storage molecule found in animal cells. It can be found in many different animal cells but is more prevalent in cells with a higher metabolic rate (those which use more energy), such as muscle cells. Glycogen is a polysaccharide which means that is is is composed of many monosaccharides joined by glycosidic bonds. In the case of glycogen, the monosaccharide of which it is composed is alpha-glucose. For this reason we call the glycosidic bonds in glycogen alpha-glycosidic bonds. These alpha-glycosidic bonds can be hydrolysed by enzymes to release individual glucose monomers which can then be used in respiration to generate energy in the form of ATP. Glycogen is also a branched polysaccharide, which means that it has multiple ends upon which hydrolase enzymes can act. This means that glycogen can be rapidly hydrolysed to release many glucose monomers in a short period of time, and thus lead to the rapid generation of ATP.