What is the end product of lactic acid fermentation?

The end product of lactic acid fermentation is lactic acid. This process occurs in certain bacteria and animal cells when oxygen is scarce, such as during intense exercise. During lactic acid fermentation, glucose is broken down into pyruvate through glycolysis, and then, in the absence of sufficient oxygen, the pyruvate is converted into lactic acid. This conversion allows for the continuous generation of ATP, albeit at a lower yield compared to aerobic respiration, which is especially important during short bursts of high energy activity.

In contrast, glucose is the substrate that undergoes fermentation rather than a product. Carbon dioxide is released as a byproduct in some fermentation processes, notably in alcoholic fermentation, but not in lactic acid fermentation. Ethanol is the primary product of alcoholic fermentation, which occurs in yeast and some types of bacteria, not in lactic acid fermentation. Thus, the correct identification of lactic acid as the end product highlights its role in anaerobic metabolism, particularly in muscle cells and certain microorganisms.