Phosphocreatine and other energy systems??

Question

Correct me if I'm wrong, but

In say for example muscular contraction ATP is first used, when that ATP is used up it is then regenerated by phosphocreatine.

Then aerobic respiration kicks in and produces more ATP...

Is the ATP produced by aerobic respiration used directly for muscle contraction or is it used to produce more phospho creatine to replenish the ATP (ADP and P) already in the muscle?

Answer 1

ATP produced by aerobic respiration is used directly for muscle contractions. Phosphocreatine acts as a reserve for ATP. Excess ATP is used to convert creatine back to phosphocreatine.