Final answer:
When muscle cells run out of oxygen, energy extraction potential from sugars decreases and they switch to anaerobic respiration through glycolysis, leading to a lower ATP yield.
Step-by-step explanation:
When muscle cells run out of oxygen, the potential for energy extraction from sugars decreases, and the cells resort to anaerobic respiration. Initially, muscle glycogen is used for energy via glycolysis, producing ATP. As more energy is demanded and oxygen becomes scarce, pyruvate is converted to lactic acid. This anaerobic process results in a lower yield of ATP compared to aerobic respiration. Glycolysis can provide some ATP, but it is much less efficient than when oxygen is available to complete aerobic respiration.
When muscle cells run out of oxygen, the potential for energy extraction from sugars decreases. The cells switch to anaerobic respiration or glycolysis to produce ATP. Glycolysis is an anaerobic process that breaks down glucose to produce ATP. When oxygen levels are low, pyruvic acid produced by glycolysis is converted to lactic acid.