Question

What is ATP and how does it act as an energy-transfer agent? What is phosphoryl transfer potential?

Answer 1

ATP stands for adenosine triphosphate, which has three phosphate groups connected in a chain. The total charge of ATP is `-4`.

ATP therefore has phosphate groups it can transfer off of it. Phosphate, `"PO"_4^(3-)`, looks like this:

After ATP transfers one phosphate group off of it, it becomes ADP, which stands for adenosine diphosphate, reflecting that it now has two phosphate groups connected in a chain.

The transferred phosphate carries with it energy stored within its bonds.

The greater the tendency or "potency" to transfer a phosphate, the greater the phosphoryl transfer potential is said to be.

The phosphoryl transfer potential of ATP is about `-"30.5 kJ/mol"`, so about `"30.5 kJ"` is carried with the free phosphate group for every `"mol"` of ATP that transfers one phosphate group.