The process that releases energy from food in the presence of oxygen is known as?

• A. Cellular respiration
• B. Photosynthesis
• C. Fermentation
• D. Anabolism

Answer: (A)

Cellular respiration is the process that releases energy from food in the presence of oxygen. In this aerobic pathway, glucose is broken down through glycolysis in the cytoplasm, pyruvate is converted to acetyl-CoA, the citric acid cycle runs, and electrons are transferred along the electron transport chain in mitochondria to drive ATP production. Oxygen acts as the final electron acceptor, forming water, which helps keep the cycle running efficiently and yields a relatively large amount of ATP. This stands in contrast to photosynthesis, which uses light energy to build sugars, fermentation, which occurs without oxygen and makes far less ATP (producing lactate or ethanol instead), and anabolism, which focuses on building complex molecules rather than releasing energy.