Which of the following is listed as an output of the Citric Acid Cycle?

• A. 2 NADH, 2 FADH2
• B. 10 NADH, 2 FAD
• C. 32-34 ATP
• D. 4 CO2, 6 NADH, 2 FADH2, 2 ATP

Answer: (D)

The Citric Acid Cycle releases carbon dioxide while capturing energy in the form of NADH, FADH2, and a small amount of direct ATP equivalent. Per glucose, the cycle runs twice because two acetyl-CoA enter from one glucose molecule. Each turn produces 1 ATP (as GTP), 3 NADH, 1 FADH2, and 2 CO2. Twice that adds up to four CO2, six NADH, two FADH2, and two ATP. These NADH and FADH2 then feed the electron transport chain to generate most of the cell’s ATP, bringing total ATP yields in the typical range. The option listing four CO2, six NADH, two FADH2, and two ATP matches the full output of the cycle per glucose.