Energy Systems Questions

[Visionz]

With the ATP-PC system, does the energy from the breakdown of CP resynthesise the ATP by attaching the phosphate molecule from the CP to the ADP? or does the energy from the CP breakdown reattach the phosphate molecule from the previous ATP > ADP split. In laymans terms, does the phosphate molecule disappear after its separated form the ATP or does it just need to be reattached?
I suck at all this bio crap side.

[vexx]

basically with the ATP-PC system:

it relies on the muscle stores of PC already in the muscles in a limited amount... so when this molecule's phosphate is removed, energy is released rapidly. and it's this energy that is used for the resynthesis of ATP from ADP + Pi. Basically the ATP system when it loses it's phosphate releases the energy for muscular contractions, the PC just acts as a fuel to resynthesis that phosphate group lost of the ADP back on. The reason the system goes for such a small amount of time is because PC is only refuelled at rest and so it cannot break down to help rebuild the ATP molecular after it is depleted in the muscle.
make sense?

[Visionz]

But what phosphate molecule joins back onto the ADP? Is it the one it just separated from or is it the one from the CP?

Epiphany.. It rejoins the same phosphate molecule that split using the energy from the CP split. And the phosphate molecule from the phosphocreatine split is reattached to the creatine molecule when the CP is replenished through a passive recovery. amirite?

[vexx]

^ yep that sounds about right!