A: You do an experiment in which you add oxaloacetate uniformly labeled with14C (ie withequal amounts of 14C in eachof its carbon atoms) along with unlabeled acetyl-CoA to an extractof mitochondria. After a single pass through the TCA cycle, whatfraction of the original radioactivity will be found in the oxaloacetate?

B: The TCA cycle is sometimes described as the major pathway of aerobic catabolism, which means that it is an oxygen-dependentprocess. However, none of the reactions of the cycle directlyinvolves oxygen as a reactant. Why is the pathwayoxygen-dependent?