Now, the final process of aerobic cell respiration, the culmination of aerobic cell respiration, is a process process we call oxidative phosphorylation, that takes place on the electron transfer chain of the inner membrane of the mitochondria. And this is what we're going to introduce in this lecture. But before we focus on the electron transport chain and oxidative phosphorylation, let's remember what happened in glycolysis, pyruvate carboxylation and the citric acid cycle. So in glycolysis, we broke down glucose into pyruvate molecules and we also formed NADH molecules and a few ATP molecules. And this took place in the cytoplasm of the cell. Now, in the presence of oxygen, the pyruvate molecules will be moved into the matrix of the mitochondria.