The citric acid cycle is a very important cycle because it's the center of aerobic respiration. It's basically the cycle where all our fuel molecules, the carbonbased fuel molecules, such as amino acids and fat molecules and glucose molecules, actually end up going. And this is where we extract the high energy electrons from these carbon fuel molecules and use those electrons on the electron transport chain to actually generate the high energy ATP molecules that are needed by the cell to carry out many different types of processes, such as contraction of our skeleton muscle cells. Now, because the citric acid cycle is so important, we actually have to regulate this citric acid cycle. We have to closely monitor its activity, in fact, even before the citric acid cycle actually begins. One point of regulation of the citric acid cycle is by regulating Pyruvate decarboxylation because remember, Pyruvate decarboxylation must take place before the citric acid cycle actually begins.