Well, the citric acid cycle is the center of glucose metabolism. This is where all these fuel molecules actually meet up to then go on and form the ATP molecule. So things like amino acids and fatty acids, they ultimately enter the citric acid cycle, or more specifically, aerobic cellular respiration as acetylcoenzy. Some amino acids can actually enter as intermediates of the citric acid cycle. And the citric acid cycle has other important functions as well. It also actually gives us those intermediate molecules, the building block molecules such as oxalo acetate molecules that we use to form many building blocks.