Question

For the hydrolysis of ATP to ADP + Pi (AGº'=-30.5kJ/mol) what is AG'when [ATP], [ADP], and [Pi] are 8, 1, and 8 mM, respectively (use RT=2.48 kJ/mol). O Select one: A. -30.5 kJ/mol x O B.-17.1 kJ/mol C. -47.6 kJ/mol D. 13.4 kJ/mol O

Answer 1

Gibbs free energy decides the feasibility of a reaction and here the standard Gibbs free energy at 298 K is given and the value is -30.5 kJ/mol.

Now, the given reaction is:

$ATP\rightarrow ADP+P_{i}$

And the concentrations are:

AT P = 8mM
; $ADP=1mM$ ; $P_{i}=8mM$

The expression that dictates the relationship between the standard Gibbs free energy and the concentration-dependent Gibbs free energy is:

AG' = AGⓇ + RTln(Q)

Here Q is the reaction quotient. where:

$Q=\frac{[ADP]\times [P_{i}]}{[ATP]}$

Now the given value of RT = 2.48 kJ/mol.

Thus, $\Delta G'=-30.5+2.48ln(\frac{[8\times 10^{-3}M]\times [1\times 10^{-3}M]}{8\times 10^{-3}M})$

$=>\Delta G'=-30.5+2.48ln( 10^{-3}M) kJ/mol$

$=>\Delta G'=-30.5-17.13 kJ/mol= -47.6 kJ/mol$

So, the answer is the option C. -47.6 kJ/mol