Overview

• In the absence of oxygen, anaerobic respiration occurs.
• In anaerobic respiration, only glycolysis occurs yielding only a little energy in the form of ATP directly (2 NET)
• The biochemical reactions involved in glycolysis produce hydrogen atoms, which must be removed. If these products are not removed and begin to accumulate, glycolysis cannot occur
• The pyruvate produced by glycolysis must be converted into another compound to prevent accumulation of hydrogen, which is lactate in mammals and ethanol in plants and yeast
• Both of these conversions P+M also involve the oxidation of the NADH produced in glycolysis, which frees the NAD to be used again in glycolysis. If this did not happen, glycolysis would stop due to no hydrogen acceptors being available.
• As there is only a net gain of 2 ATP from glycolysis, anaerobic respiration is a very inefficient process in comparison to aerobic respiration. However, anaerobic respiration is a relatively fast process that can take place throughout the cytoplasm and substances do not have to diffuse into the mitochondria
• anaerobic respiration can only use glucose (or other carbohydrate fructose) as a respiratory substrates such as fat and proteins enter the respiratory pathway beyond glycolysis