Which organelle uses oxygen as an electron acceptor to produce ATP?

• A. Mitochondria
• B. Chloroplast
• C. Nucleus
• D. Ribosome

Answer: (A)

Oxidative phosphorylation in mitochondria uses oxygen as the final electron acceptor to drive ATP production. During aerobic respiration, electrons move through the mitochondrial electron transport chain and oxygen accepts these electrons, forming water. This transfer creates a proton gradient across the inner mitochondrial membrane, which powers ATP synthase to convert ADP into ATP. Chloroplasts perform ATP production during photosynthesis using light energy, with NADP+ acting as the final electron acceptor, and oxygen is released as a byproduct—not used to make ATP in that pathway. The nucleus and ribosomes aren’t involved in ATP generation via the electron transport chain.