Humber Admissions Practice Test

During anaerobic metabolism, what is the primary byproduct of glucose breakdown?

1. Oxygen

2. ATP

3. Lactate

4. Carbon dioxide

The correct answer is: Lactate

During anaerobic metabolism, the primary byproduct of glucose breakdown is lactate. This process occurs when the body generates energy in the absence of sufficient oxygen. When glucose is metabolized anaerobically, it undergoes glycolysis, which converts glucose into pyruvate. In the absence of oxygen, pyruvate is then converted into lactate instead of being further processed in the mitochondrial oxidative pathways, which require oxygen. This production of lactate is significant because it allows the cell to continue producing ATP (the energy currency of the cell) under low-oxygen conditions, although much less efficiently than aerobic metabolism. The accumulation of lactate can lead to muscle fatigue, but it also serves as a temporary solution for energy production during intense physical activities where oxygen supply is limited. In contrast, while ATP is indeed produced during this process, it is not a byproduct but rather the primary energy carrier that is produced. Oxygen is required for aerobic metabolism, not for anaerobic. Carbon dioxide is a byproduct of aerobic metabolism rather than anaerobic. Hence, the correct identification of lactate as the main byproduct in anaerobic metabolism is fundamental to understanding how our body responds to limited oxygen conditions during physical exertion.