The Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid cycle, is a series of chemical reactions that occur in every cell that uses oxygen to produce energy. It is a metabolic pathway composed of eight enzymes, all of which are within the mitochondrial matrix except the outlier succinate dehydrogenase, which is related to the respiratory chain on the inner mitochondrial membrane. The cycle serves as a gateway for aerobic metabolism for molecules that can convert to an acetyl group or dicarboxylic acid. The Krebs cycle is used to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. The cycle provides precursors of certain amino acids, as well as the reducing agent NADH, that are used in numerous other reactions. The Krebs cycle is controlled and regulated by the availability of the NAD+ and FAD substrates, while high concentrations of NADH inhibit it. The cycle is also crucial during development, as the energy obtained from this metabolic pathway is essential for the adequate growth of the endothelial system, which will guide the formation of the blood and lymphatic vessels.