Two ATP molecules can be produced per glucose molecule during anaerobic respiration, reports Eugene McCarthy, Ph.D., of Online Biology Dictionary. The steps of anaerobic metabolism consist of glycolysis to produce pyruvic acid, followed by its metabolism in the cytoplasm. Anaerobic respiration is much less efficient than aerobic metabolism.
During respiration, glucose is oxidized and broken down into adenosine triphosphate and side products, according to McCarthy. ATP stores energy that is then consumed during various cellular processes. Anaerobic respiration occurs in environments that lack oxygen, such as during fermentation. It yields less ATP than aerobic metabolism due to the higher energy of the side products, which include ethanol or lactic acid.