And finally, let's discuss the citric acid cycle. So it turns out that the citric acid cycle actually is involved in forming the majority of the ATP molecule. So in the citric acid cycle, we form six NADH molecules. And because this occurs in the mitochondrial matrix, we have six multiplied by three. So 18 ATP molecules are formed when the six NADH end up on the electron transport chain. Because we have two fadh two molecules and each one forms two ATP, we have a total of four ATP molecules form when the fadh twos are on our electron transport chain.