Multiple choice

How many ATP are formed in Krebs Cycle through ETS

  1. 12

  2. 11

  3. 10

  4. 1
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

One turn of the Krebs cycle produces 3 NADH, 1 FADH2, and 1 GTP/ATP. Using the conversion factors (2.5 ATP per NADH, 1.5 per FADH2), the total is 3(2.5) + 1(1.5) + 1 = 10. However, if counting the pyruvate dehydrogenase step (1 NADH), the total is 12.5. Given the options, 11 is often cited in specific contexts or textbooks.

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