Question

When acetyl CoA enters the TCA it forms the 6C product citrate. This is decarboxylated to a 4C compound as it passes through the TCA cycle. Did the two carbons that were lost from citrate come from the original acetyl CoA that entered the cycle at the beginning

Answer 1

NO

Step-by-step explanation:

No, the two carbon atoms that are lost from the TCA in the form of carbon dioxide didn’t come from the acetyl CoA. Isotope labeling analysis has shown that the two carbons of acetyl CoA can be lost in the second or third run of the cycle but not in the first run.