Pyruvic acid can be made from glucose through glycolysis. One molecule of glucose breaks down into two molecules of pyruvate. These are then used to give more energy to living animals, plants and microorganisms. It is then changed back to carbohydrates (such as glucose) by a metabolic chemical reaction named gluconeogenesis, or to fatty acids through a similar reaction. It can also be used to make the amino acid alanine and can be converted into ethanol or lactic acid by fermentation.