Chapter 16, Problem 83QRT

Another step in the metabolism of glucose, which occurs after the formation of glucose 6-phosphate, is the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate (“bis” means two):

Fructose 6-phosphate(aq) + H₂PO₄⁻ (aq) → fructose l,6-bisphosphate(aq) + H₂O(ℓ) + H⁺(aq)

1. (a) This reaction has a Gibbs free energy change of +16.7 kJ/mol of fructose 6-phosphate. Is it endergonic or exergonic?
2. (b) Write the equation for the formation of 1 mol ADP from ATR for which Δ_rG° = −30.5 kJ/mol.
3. (c) Couple these two reactions to get an exergonic process; write its overall chemical equation, and calculate the Gibbs free energy change.