What is the function of pyruvate in cellular respiration?

Pyruvate is involved in several steps of cellular respiration including glycolysis, where it is the product of glucose being broken down, the Kreb's cycle uses the pyruvate to complete its process as well. During vigorous exercise, pyruvate is turned into lactate to give more energy to the oxygen-starved muscles.

The pyruvate's original form is reduced during the first cycle of cellular respiration because the energy in some of its carbon molecules has been used up. These are expelled from the body as carbon dioxide so that the remaining molecules can move onto the next step without wasting any energy that remains in the cells, so that it can be used to make lactate and adenosine triphosphate.