Because once the citric acid cycle takes place and once we abstract all these electrons from these molecules, the carbon fuel molecules, these electrons, which are carried by NADH molecules and Fadh two molecules, can now move on to a series of proteins on the inner mitochondrial membrane we call the electron transport chain. And these series of proteins shown here basically allow the movement of these electrons down their potential gradient. And as electrons flow along these protein membranes on the membrane of the mitochondria, that generates a proton gradient across the two sides of the membrane. And as the proton gradient is generated, that is then used to basically create ATP molecules. So it's not the citric acid cycle that creates the ATP, but it's the oxidative osphorylation processes that take place across electron transport chain proteins that ultimately forms these ATP molecules. So notice that no high energy ATP molecules are actually formed in the citric acid cycle.