Affinity of ADP

[hannahzarzar]

The ∆Go’ of the reaction acetyl phosphate + ADP ⇌ acetate +ATP is -2.8 kcal/mol. Molecule for molecule, acetyl phosphate has (greater, lesser, equal) free energy than does ATP relative to its dephosphorylated compound; ADP has (greater, lesser, equal) affinity for phosphate than acetate. Circle the correct answer.

I believe the first answer is equal, because acetyl phosphate + ADP is the same as ATP, and I think the answer to the second part is greater. Is this correct?

[JackBean]

1) it cannot be equal, as the G0 is non-zero.

2) it has to be opposite for both possibilities.

3) Look on the sign of G0 (+/-) and from that guess, which way is prefered

[hannahzarzar]

So, it has to be greater for the first and lesser for the second.

[JackBean]

I think so

[hannahzarzar]

But that would mean (in the second part) that ADP has less of a pull to phosphate than to acetate. Could that be right??