Question

The standard free energy change for ATP hydrolysis is -30.5 kJ/mol. Therefore, the free energy change for this reaction in a cell in which the concentration of ATP, ADP, and Pi are 3.1 mM, 2.2 mM and 6.8 mM, respectively, and assuming a physiologically relevant temperature (37 °C), is:

Answer -44.25 kJ/mol explain

Answer 1

Given, G⁰ = -30.5 KJ/mol = -30500 J/mol

[ATP] = 3.1 mM = 0.0031 M

[ADP] = 2.2 mM = 0.0022 M

[P_i] = 6.8 mM = 0.0068 M

T = 37⁰C = (37 +273) K = 310 K

We have the relation as---

G = G⁰ + RTlnK

=> G = G⁰ + RT ln( [ADP] [P_i] / [ATP] )

=> G = -30500 J/mol + 8.314 J/mol K x 310 k x ln ( 0.0022 x 0.0068 / 0.0031)

=> G = -30500 J/mol + 2577.34 J/mol x ln (0.004825806452)

=> G = -30500 J/mol + 2577.34 J/mol x ( -5.33377418)

=> G = -30500 J/mol -13746.95789 J/mol

=> G = -44246.95789 J/mol

=> G = -44.25 KJ/mol