alleryStart learning →How is oxaloacetate regenerated at the end of the citric acid cycle?
ABy reducing fumarate with FAD
BBy oxidizing malate to make NADH
CBy splitting citrate into two halves
DBy adding coenzyme A to succinate
Answer & Solution
Correct answer: B. By oxidizing malate to make NADH
1. Water is added to fumarate during step seven, and malate is produced.
2. The last step regenerates oxaloacetate by oxidizing malate.
3. Another molecule of NADH is produced in that oxidation.
4. Regenerating oxaloacetate is what closes the loop so the cycle can accept a fresh acetyl group.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 7 "Cellular Respiration", section 7.3 Oxidation of Pyruvate and the Citric Acid Cycle_
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