Which step of aerobic respiration actually consumes oxygen?

• A. Electron Transport Chain
• B. Krebs Cycle
• C. Fermentation
• D. Glycolysis

Answer: (A)

Verified step by step guidance

1. Understand the process of aerobic respiration, which includes Glycolysis, the Krebs Cycle, and the Electron Transport Chain.
2. Recognize that Glycolysis occurs in the cytoplasm and does not require oxygen, thus it does not consume oxygen.
3. Identify that the Krebs Cycle takes place in the mitochondria and produces electron carriers, but it does not directly consume oxygen.
4. Note that Fermentation is an anaerobic process, meaning it occurs without oxygen, so it does not consume oxygen.
5. Focus on the Electron Transport Chain, which is the final stage of aerobic respiration occurring in the inner mitochondrial membrane, where oxygen acts as the final electron acceptor, thus consuming oxygen.