There are many ways living organisms convert consumed energy into usable energy. The foods we consume provide us nutrients and our body breaks down those nutrients to convert them into usable energy like ATP or adenosine triphosphate. Plants, bacteria and other microorganisms, all animals and human beings have a process that facilitates the breakdown of the consumed energy, conversion into usable energy and eventual absorption of the energy by the various living cells. One primary facilitator of the whole process is respiration. There are primarily two types of respiration: aerobic and anaerobic. The third type of respiration or the process facilitating the conversion of energy is fermentation.
Aerobic respiration depends on oxygen. Aerobic respiration is not possible unless the organism can absorb oxygen in some way and use it to break down the consumed energy. In the absence of oxygen, anaerobic respiration takes place. Fermentation is often confused with anaerobic respiration because it also doesn’t require oxygen or happens in the absence of oxygen. However, fermentation and anaerobic respiration are not the same.
Difference Between Fermentation and Anaerobic Respiration
Aerobic respiration starts with glycolysis. It is a process wherein carbohydrate, sugar or glucose, whichever term you prefer, is broken down and it loses a few electrons then forms pyruvate. Since oxygen is available, it acts as the electron acceptor. The process progresses after oxygen accepts the electrons and ends with generating 2 ATP.
Fermentation has the same process as aerobic respiration but it continues the chain without having oxygen as the electron acceptor. The process of glycolysis doesn’t produce pyruvate. For instance, when human beings don’t get enough oxygen due to excessive physical activity or for other reason, there is lactic acid fermentation in the muscles. Marathon runners often suffer from muscle cramps caused by lactic acid buildup which is formed through fermentation. Many living organisms produce alcohol instead of pyruvate and lactic acid. Although fermentation is a process that leads to breaking down of available energy into usable energy, it is not respiration.
Anaerobic respiration starts with glycolysis and it too generates 2 ATP. But it does so with oxygen. It doesn’t make pyruvate but acetyl coenzyme A. Thereon the process enters the citric acid cycle. The electron acceptor, which is oxygen in case of aerobic respiration, can be sulfate ions, nitrate ions or carbon dioxide in case of anaerobic respiration.
Both anaerobic respiration and fermentation are more primitive. Aerobic respiration is more evolved.
