Anaerobic respiration (anaerobiosis) refers to the oxiation of molecules in the absence of oxygen to produce energy, in opposition to aerobic respiration which does use oxygen. Anaerobic respiration processes require another electron acceptor to replace oxygen. Anaerobic respiration is often used interchangeably with fermentation, especially when the glycolytic pathway is used for energy production in the cell. They are not synonymous terms, however, since certain anaerobic prokaryotes can generate all of their ATP using an electron transport system and ATP synthase. Definition of anaerobic respiration: the breakdown of food substances in the absence of oxygen with a small amount of energy. General word and symbol equations for the anaerobic respiration of glucose can be shown as