Respiration is a chemical reaction that can be expressed by the equation C6H12O6 plus 6O2 yields 6CO2 and 6H2O. This generally states that glucose and oxygen yield carbon dioxide and water. An aerobic reaction of this nature releases approximately 3,000 kilojoules per mole of material in the reaction.
Enzymes in biological bodies regulate the rate of respiration to sustain long-term energy production from carbohydrates and fats. Another form of respiration is anaerobic in nature, meaning without air, and involves metabolizing glucose directly into energy with a by-product of lactic acid. Anaerobic respiration has a few disadvantages, including that it only provides about 120 kilojoules per mole of material and the lactic acid produced is generally poisonous and requires oxygen to break it down to a non-poisonous level.