Use of Energy by the Human Body

782 WordsFeb 26, 20183 Pages
Throughout a normal day, the body uses glucose in the form of energy. The glucose that the body uses is attained from carbohydrates that one receives from a meal eaten during the day. However, when glucose begins to run out, especially if a person is rigorously exercising, and is not “restocked,” the body must use its energy supplies, glycogen. Glycogen is one of the most important polysaccharides in the human body. It is the body’s stored energy; with the highest storing sites being the muscles and liver. Glycogen is important to the liver because it is able to provide a backup supply of glucose so that blood glucose concentration is maintained at a sufficient level to supply the brain during times of starvation. Glycogen's function in sustaining blood-glucose levels is imperative because glucose is essentially the only fuel source used by the brain. The primary function of muscle glycogen is to supply fuel for the contraction of the muscles during exercise. However, insufficient amount of glycogen in the liver and muscles can lead to numerous diseases, diseases like Glycogen Storage Disorders (GSD). Glycogen synthesis and breakdown occur by distinctive pathways that are catalyzed by different enzymes. Glycogen phosphorylation involves three steps: the first is the release of glucose 1-phosphate from glycogen, then altering of the glycogen substrate to allow additional phosphorylation, and last is the conversion of glucose 1-phosphate to glucose 6-phosphate. Glycogen
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