Final answer:
Respiration produces more ATP per molecule of glucose in the presence of oxygen because oxygen is the final electron acceptor in the electron transport chain of aerobic respiration, enabling the complete breakdown of glucose into carbon dioxide and water, producing approximately 36-38 ATP molecules, compared to only two ATP molecules produced under anaerobic conditions.
Step-by-step explanation:
Respiration produces more ATP per molecule of glucose in the presence of oxygen than it does when oxygen is absent because oxygen plays a crucial role as the final electron acceptor in the electron transport chain of aerobic respiration. In the initial steps of glucose breakdown, only two molecules of ATP are produced. However, later steps under aerobic conditions, involving the electron transport chain and oxidative phosphorylation, release much more ATP. Specifically, for each glucose molecule, aerobic respiration generates approximately 36-38 ATP molecules. On the contrary, anaerobic respiration, which occurs in the absence of oxygen, results in the production of only about two ATP molecules because it relies solely on glycolysis followed by fermentation.
We need to breathe in oxygen so that it can be transported through our blood to our cells, where it is used for cellular respiration. Cellular respiration functions best in the presence of oxygen; otherwise, the amount of ATP production is greatly reduced. With oxygen, glucose can be fully broken down into carbon dioxide and water, releasing enough energy to generate a significant amount of ATP. This is essential for organs and tissues such as resting or moderately active muscles, which derive approximately 95 percent of their ATP requirements through aerobic respiration.
Overall, the advantages of aerobic respiration over anaerobic respiration include the higher ATP yield and the complete breakdown of glucose to carbon dioxide, which is a much more efficient way to release and harness energy stored in glucose.