Question

Muscle contraction depends on ATPATP hydrolysis. During periods of intense exercise, muscle cells rely on the ATPATP supplied by three metabolic pathways: glycolysis, mitochondrial respiration, and the phosphagen system. Figure 1 shows the rates at which the three metabolic pathways produce ATPATP following the start of an intense period of exercise.

Which of the following correctly uses the data to justify the claim that the phosphagen system is an immediate, short-term source of ATPATP for muscle cells?

Answer 1

The phosphagen system is an immediate, short-term source of ATP for muscle cells because it rapidly produces ATP through the breakdown of creatine phosphate, providing immediate energy availability in the initial stages of intense exercise.

Step-by-step explanation:

The phosphagen system is an immediate, short-term source of ATP for muscle cells. This is justified by the fact that during periods of intense exercise, the phosphagen system produces ATP at a higher rate compared to glycolysis and mitochondrial respiration. While glycolysis and mitochondrial respiration provide ATP for longer durations, they require more time to generate ATP. In contrast, the phosphagen system rapidly produces ATP through the breakdown of creatine phosphate, allowing for immediate energy availability in the initial stages of intense exercise.