In presence of oxygen, the cells convert glucose into energy through a process called:

• A. Anaerobic metabolism
• B. Perfusion
• C. Aerobic metabolism
• D. Respiration

Answer: (C)

When oxygen is available, cells generate energy mainly through aerobic metabolism, also known as cellular respiration. In this pathway, glucose is fully oxidized in the mitochondria using oxygen as the final electron acceptor. The process runs through glycolysis, the Krebs cycle, and the electron transport chain, producing carbon dioxide, water, and a large amount of ATP. This high energy yield is why oxygen presence is crucial for sustained cellular work.

Anaerobic metabolism happens without oxygen and yields far less ATP, often with lactate as a byproduct. Perfusion is about delivering blood to tissues, including oxygen and nutrients, not the energy-producing process itself. Respiration typically refers to breathing or gas exchange, not the internal cellular pathway. So the energy-producing process in the presence of oxygen is aerobic metabolism.