MCAT Biochemistry Question 140: Answer and Explanation

Home > MCAT Test > MCAT biochemistry practice tests

Test Information

Question: 140

5. In glucose degradation under aerobic conditions:

  • A. oxygen is the final electron acceptor.
  • B. oxygen is necessary for all ATP synthesis.
  • C. net water is consumed.
  • D. the proton-motive force is necessary for all ATP synthesis.

Correct Answer: A

Explanation:

This question is testing our general knowledge of cellular respiration. Notice that all types of cellular respiration (aerobic and anaerobic) start with the degradation of glucose by glycolysis. In aerobic respiration, oxygen is the final electron acceptor, and water is therefore produced at the end of the electron transport chain. While oxygen is needed for aerobic respiration in order to produce the optimal 32 molecules of ATP per glucose, it is not the only method by which ATP is produced. Glycolysis still provides 2 ATP per glucose without the need for oxygen, thus making choices (B) and (D) incorrect. Water, mentioned in choice (C), is produced in aerobic metabolism, not consumed.

Previous       Next