Question

Which one yields the maximum energy?

• A. Krebs cycle
• B. Anaerobic respiration
• C. Glycolysis
• D. Aerobic respiration.

Answer 1

Answer: (D)

Aerobic respiration.

Maximum number of ATP is generated per glucose molecule oxidation by aerobic respiration.

Glycolysis gives 2 ATP by substrate-level phosphorylation and 2 NADH yields 6 ATP (assuming 3 ATP per NADH) by oxidative phosphorylation, Transition Reaction gives 2 NADH yields 6 ATP (assuming 3 ATP per NADH) by oxidative phosphorylation, citric acid cycle gives 2 ATP from substrate-level phosphorylation, 6 NADH yields 18 ATP (assuming 3 ATP per NADH) by oxidative phosphorylation, 2 FADH${}_2$ yields 4 ATP (assuming 2 ATP per FADH${}_2$) by oxidative phosphorylation. So the total maximum yield of ATP generated from one glucose molecule is 38 ATP: 4 from substrate-level phosphorylation; 34 from oxidative phosphorylation.

So the correct option is 'Aerobic respiration'.