And in the matrix, we're going to prepare the pyruvate molecules for the citric acid cycle by a process called pyruvate carboxylation. So we form acetylco enzyme A molecules, and those acetyl coenzyme A molecules are then moved into the citric acid cycle, which also takes place in the matrix of the mitochondria. So in the cytoplasm, we have glycolysis, but inside the matrix, we have the citric acid cycle and pyruvate carboxylation. Now, the entire point of the citric acid cycle is to actually further oxidize the glucose derivative molecules so that we can extract those high energy electrons and place those high energy electrons onto special calorie molecules we call NAD plus an fad. Now, what's the point of extracting these high energy electrons? Well, the point of extracting these high energy electrons is to use the high energy electrons to basically oxidatively phosphorylate ADP molecules into ATP molecules along the electron transport chain.