Final answer:
The primary byproduct of anaerobic glycolysis in muscle during periods of high-intensity exercise, where oxygen supply is low, is lactic acid. This lactic acid is created from the metabolization of glucose or the breakdown of muscle glycogen, and while it can contribute to muscle fatigue, it can be recycled by the liver into usable energy.
Step-by-step explanation:
Glycolysis and its Byproduct in Anaerobic Muscle Energetics
During vigorous muscle activity, when oxygen levels are insufficient for aerobic metabolism, muscles rely on anaerobic glycolysis for ATP production. Anaerobic glycolysis involves the breakdown of glucose derived from blood glucose or muscle glycogen. This process yields two molecules of ATP and two molecules of pyruvic acid per glucose molecule. However, due to the lack of oxygen, pyruvic acid is reduced to lactic acid, which acts as a byproduct of the glycolysis pathway under anaerobic conditions.
The accumulation of lactic acid in muscles can contribute to fatigue, but the body can adapt through training to improve the efficiency of anaerobic metabolism. Lactic acid can also be transported to the liver where it is converted back to pyruvate and glucose, which can then re-enter the energy production cycle. Hence, the primary byproduct of anaerobic glycolysis during high-intensity exercise is lactic acid.