Question

In the first step of glycolysis, the given two reactions are coupled. reaction 1:reaction 2:glucose+Pi⟶glucose-6-phosphate+H2OATP+H2O⟶ADP+PiΔG=+13.8 kJ/molΔG=−30.5 kJ/mol reaction 1:glucose+Pi⟶glucose-6-phosphate+H2OΔG=+13.8 kJ/molreaction 2:ATP+H2O⟶ADP+PiΔG=−30.5 kJ/mol Answer the four questions about the first step of glycolysis. Is reaction 2 spontaneous or nonspontaneous?

Answer 1

Answer : The reaction 2 is spontaneous.

Explanation :

As we know that:

$\Delta G$= +ve, reaction is non spontaneous

$\Delta G$= -ve, reaction is spontaneous

$\Delta G$= 0, reaction is in equilibrium

For the reaction to be spontaneous, the Gibbs free energy of the reaction must come out to be negative.

Reaction 1:

Glucose + Pi $\rightarrow$ glucose-6-phosphate + H₂O,   ΔG = +13.8 kJ/mol

Reaction 2:

ATP + H₂O $\rightarrow$ ADP + Pi,   ΔG = -30.5 kJ/mol

From this we conclude that the value of ΔG is negative. So, reaction 2 is a spontaneous reaction.