Complete oxidation of one acetyl-CoA through one turn of the TCA cycle, with all reduced cofactors entering the electron transport chain, yields a net of approximately how many ATP equivalents (using current P/O ratios)?
- A 6.5
- B 10 ✓
- C 12
- D 15
Correct answer: B. 10
Explanation
One turn of the cycle produces 3 NADH (about 2.5 ATP each, totaling 7.5), 1 FADH2 at Complex II (about 1.5 ATP), and 1 GTP from succinyl-CoA synthetase, summing to approximately 10 ATP per acetyl-CoA. Older textbooks citing 12 used the outdated integer P/O values of 3 and 2, which modern measurements have revised downward. The figure 15 has no basis for a single acetyl-CoA.
Reference: Lippincott Illustrated Reviews: Biochemistry, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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