The Krebs cycle occurs in the mitochondrial matrix and generates a pool of chemical energy (ATP, NADH, and FADH2) from the oxidation of pyruvate, the end product of glycolysis. Pyruvate is transported into the mitochondria and loses carbon dioxide to form acetyl-CoA, a 2-carbon molecule.
During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of reactions that give off energy. The high-energy electrons that are produced are picked up by a series of electron carriers, and the energy is used to convert ADP into ATP.
