Final answer:
The aerobic phase of glucose catabolism occurs in the mitochondria of the cell following glycolysis in the cytoplasm. Oxygen presence allows pyruvate to enter the Krebs cycle and oxidative phosphorylation for efficient ATP production.
Step-by-step explanation:
The aerobic phase of glucose catabolism takes place in the mitochondria of the cell. Glycolysis, the initial stage of glucose catabolism, occurs in the cytoplasm and produces pyruvate from glucose. Pyruvate is then transported into the mitochondria, where it undergoes the Krebs cycle and oxidative phosphorylation to produce ATP.
While glycolysis can happen without oxygen and thus be considered anaerobic, the presence of oxygen enables pyruvate to enter the mitochondria for the aerobic process which is responsible for the majority of ATP production in the cell.During vigorous activities, if oxygen is limited, cells may revert to anaerobic glycolysis, producing lactic acid in the process. However, under normal conditions, the brain and skeletal muscles primarily rely on aerobic glycolysis. The brain depends solely on glucose from the blood for this process since it does not store glycogen whereas muscles can utilize glycogen reserves for glycolysis before relying on glucose from the bloodstream. The regulation of glycolysis is influenced by the balance of ATP to ADP, as high ATP concentrations inhibit the pathway, and low ATP concentrations stimulate the process.