Anaerobiosis is another name for anaerobic respiration, a type of cellular respiration that does not use oxygen. Cellular respiration is a way for cells to obtain energy by converting nutrients into adenosine triphosphate, or ATP. Anaerobiosis takes place in the cytoplasm in the forms of glycolysis and fermentation.
Glycolysis allows for both aerobic and anaerobic respiration through the breakdown of glucose. Fermentation enables anaerobic respiration by donating electrons and hydrogen ions produced through glycolysis to other molecules. Fermentation is also used by muscle cells to make lactic acid, which the body needs for energy during periods of low oxygen levels.