Glucose metabolism is the process by which the body breaks down glucose, a simple sugar, to produce energy. This process primarily occurs in the cells of the body, where glucose is converted into ATP (adenosine triphosphate), the energy currency of the cell. The breakdown of glucose can occur through two main pathways: glycolysis, which happens in the cytoplasm, and aerobic respiration, which takes place in the mitochondria when oxygen is present. During glycolysis, one molecule of glucose is split into two molecules of pyruvate, generating a small amount of ATP. If oxygen is available, pyruvate enters the mitochondria for further processing in the Krebs cycle and electron transport chain, producing more ATP. If oxygen is scarce, pyruvate can be converted into lactic acid or ethanol, depending on the organism. This metabolic flexibility allows the body to efficiently manage energy production