Under aerobic conditions, what happens to pyruvate after glycolysis?

• A. It enters mitochondria and is oxidized to CO2 and H2O
• B. It is converted to lactate
• C. Stored as glycogen
• D. Directly used to form glucose

Answer: (A)

Under aerobic conditions, pyruvate from glycolysis is moved into the mitochondria where it is converted to acetyl-CoA by the pyruvate dehydrogenase complex, releasing CO2 and producing NADH. The acetyl-CoA then feeds the Krebs cycle, generating more NADH and FADH2, and these carriers drive the electron transport chain to produce ATP, with oxygen acting as the final electron acceptor to form water. This sequence results in complete oxidation to CO2 and H2O, which is why the end products are CO2 and H2O. Lactate formation occurs when there isn’t enough oxygen, glycogen storage involves glucose rather than pyruvate directly, and gluconeogenesis can use pyruvate to make glucose but is not the immediate fate under aerobic conditions.