Final answer:
Glycogen, stored in the liver and muscle cells, is the main energy storage form of glucose in vertebrates. Its highly branched structure allows for fast mobilization of glucose during energy-demanding situations, offering a quick source of glucose to maintain metabolic balance.
Step-by-step explanation:
Glycogen is a polysaccharide of glucose and serves as the main energy storage form of glucose in humans and other vertebrates. It is predominantly found in the liver and muscle cells. Structurally, glycogen is a highly branched molecule, which allows for rapid release of glucose units when energy is immediately required. This branched structure provides advantages during periods of fasting, as well as during high-energy activities, such as vigorous exercise. The liver's glycogen serves to maintain blood glucose levels, while muscle glycogen is directly accessible by muscle cells to fuel contraction.
Structure and Advantage of Glycogen's Formation
Glycogen has a branched configuration, with up to 106 D-glucose units joined by alpha-1,4-glycosidic linkages and branches through alpha-1,6-glycosidic linkages, much like amylopectin. The branches occur at intervals of every 10 to 15 glucose units, making glycogen more soluble and easier to hydrolyze, thus facilitating a rapid increase in blood glucose when needed. This structural organization means more glucose can be released swiftly via a process known as glycogenolysis—this capacity to quickly mobilize glucose stores provides an optimal energy source when immediate glucose is necessary, making it a highly efficient energy reserve molecule.