The _______ stored by the liver cells releases into the blood for utilization by all body cells.

This is the main storage poly-saccharide in animals. Hence, it is commonly called animal starch. Blue-green algae and fungi store glycogen as fuel reserve. Like those of amylopectin, glycogen molecules are also large and highly branched (branch points are a, 1—6 linkages) polymers of thousands of D-glucose residues linked by a, 1-4 glycosidic bonds . In comparison to amylopectin molecules, however, glycogen molecules are much larger, more extensively branched and more compactly coiled concentrically. Vertebrate animals store glycogen in liver and skeletal muscles. Stored glycogen may respectively account for upto 10% and 2% of liver and muscles by weight in man and other animals. Thus, a total of about 400 grams of glycogen (about 100 gm in liver and about 300 gm in skeletal muscles) is normally found in the body of an average adult human being. In liver cells, the glycogen is found in large, flattened and ellipsoidal grains. Each grain is a cluster of small granules and each granule is a single, compact glycogen molecule. Like amylopectin, glycogen gives a red-violet colour when treated with iodine. To be used in cells for energy, it is broken down by hydrolysis into its glucose monomers (glycogenolysis), but only liver cells release this glucose into the blood for utilization by all body cells. Glycogen stored in muscle cells is utilized only by these cells themselves.