Glycogen

Glycogen is a storage polysaccharide, sometimes called 'animal starch', and is the only form in which carbohydrate is stored in animals and fungi. Structurally it resembles amylopectin - a polymer of glucose units - but it is even more highly branched, carrying frequent alpha(1->6)-linked branch points in addition to its main alpha(1->4)-linked backbone. This dense branching allows glycogen to be broken down and rebuilt rapidly, releasing or storing large amounts of glucose quickly when the body's energy demand changes. Glycogen is stored mainly in liver cells and skeletal muscle fibres, and is found throughout most of the human body except the brain. Its synthesis from glucose is called glycogenesis, and its breakdown back to glucose (for example w …