Pyruvic acid splits apart and joins together with coenzyme A right before the Krebs Cycle, according to the CK-12 Foundation. It then forms a compound known as acetyl-CoA.
A two-carbon molecule is created from the joining together of pyruvic acid, and the remaining carbon molecule joins with oxygen to form carbon dioxide. The coenzyme A is converted to citric acid, and the carbon dioxide is then released as a waste product. At this time, high-energy electrons are released and captured within NADH. The glycolysis stage forms two pyruvic acid molecules when the glucose splits apart. Sixteen energy-carrier molecules are created as a byproduct of the Krebs Cycle, making it an efficient means of producing energy from the cell. The Krebs Cycle is the second stage of cellular respiration.