Question

You have a critical biochemical reaction that needs to occur in cells to allow glucose metabollsm. The change in Gibbs Free Energy is 12.3 kJ/mol. Which of the following reactions would be appropriate to couple this reaction to ensure metabolism occurs?

A. 20 kJ/mol
B. 10 kJ/mol
C. −20 kJ/mol
D. −10 kJ/mol

Answer 1

The biochemical reaction with a Delta G of 12.3 kJ/mol should be coupled with an exergonic reaction, in this case, the one with a change in Gibbs Free Energy of -20 kJ/mol, to ensure glucose metabolism takes place.

Step-by-step explanation:

To ensure that glucose metabolism occurs despite a biochemical reaction needing a Gibbs Free Energy change of 12.3 kJ/mol, this reaction must be coupled with one that is exergonic, meaning it releases energy. Since the choices given are in terms of energy change, the appropriate reaction to couple with would need to have a negative Delta G that is larger in magnitude than the 12.3 kJ/mol required for the endergonic reaction. Thus, the correct reaction to couple with is C. −20 kJ/mol, which would provide enough energy to drive the metabolism of glucose forward.