Question

Another biochemical reaction that produces ATP involves the conversion of acetylphosphate (CH3CO2PO3H2) to acetic acid and phosphoric acid. CH3CO2PO3H2 + H2O → HC2H3O2 + H3PO4, ΔGº = -46.9 kJ c) Write the balanced chemical equation that shows the coupling of the acetylphosphate hydrolysis reaction and the ATP synthesis reaction. Determine the free energy change.

Answer 1

Given,

CH3CO2PO3H2 + H2O → HC2H3O2 + H3PO4,       ΔGº = -46.9 kJ / mol

We know that a coupling process links a spontaneous reaction with a non spontaneous one.

The energy released in acetyl phosphate reaction provides the energy needed for the conversion of ADP to ATP

We also know that

ADP + H3PO4 -----> ATP + H2O     ΔGº = 30.6 kJ / mol

The coupled reaction is:

CH3CO2PO3H2 + H2O → HC2H3O2 + H3PO4,       ΔGº = -46.9 kJ / mol

ADP + H3PO4 -----> ATP + H2O     ΔGº = 30.6 kJ / mol

NET REACTION: CH3CO2PO3H2 + ADP -----> HC2H3O2 + ATP

ΔGº coupled reaction = - 46.9 + 30.6 = - 16.3 kJ / mol