Which statement correctly compares aerobic respiration with fermentation?

• A. Fermentation yields more ATP than aerobic
• B. Fermentation uses oxygen as final electron acceptor
• C. Aerobic respiration yields about 30–32 ATP per glucose; fermentation yields 2 ATP
• D. Aerobic respiration requires glycolysis

Answer: (C)

The key idea is the difference in energy yield and oxygen use between aerobic respiration and fermentation. In aerobic respiration, glucose is fully oxidized through glycolysis, the pyruvate step, the citric acid cycle, and oxidative phosphorylation. Oxygen acts as the final electron acceptor in the electron transport chain, allowing a large amount of ATP to be produced by phosph from the proton gradient. That full process typically yields about 30–32 ATP per glucose, though exact numbers can vary by organism and shuttle systems.

In fermentation, there is no functional electron transport chain operating to extract that much energy; electrons from NADH are dumped back into pyruvate or a derivative to regenerate NAD+, enabling glycolysis to continue, but only a small amount of ATP is produced—about 2 ATP per glucose. Fermentation also generates the fermentation products like lactate or ethanol, but the crucial point for the comparison is the much lower ATP yield and the lack of reliance on oxygen.

So the statement that aerobic respiration yields roughly 30–32 ATP per glucose while fermentation yields about 2 ATP captures the big difference in energy efficiency and explains why aerobically respiring cells produce far more ATP than those relying on fermentation. The other points are less precise descriptions of the systems: fermentation doesn’t use oxygen as the final electron acceptor, aerobic respiration isn’t defined by yielding less ATP, and while glycolysis is shared, saying aerobic respiration requires glycolysis doesn’t compare the two processes as clearly.