On top of that, as we'll see in a future lecture, the citric acid cycle is also actually used to synthesize many types of building block molecules used by ourselves. Now, there are three ways by which we can actually regulate the citric acid cycle. The first method is what we discussed previously. It's by regulating pyruvate decarboxylation. So remember that inside the cytoplasm, glucose molecules undergo glycolysis to form pyruvate. And in the presence of oxygen, the pyruvate moves into the matrix of the mitochondria, where we undergo pyruvate to carboxylation.