Final answer:
A non-spontaneous condensation reaction can be driven by coupling it with the exergonic reaction of ATP hydrolysis. This coupling makes the overall free energy change negative, thus allowing the reaction to proceed spontaneously.
Step-by-step explanation:
A condensation reaction, which is non-spontaneous, can be driven by ATP hydrolysis. The hydrolysis of ATP into ADP and a phosphate group is an exergonic reaction, releasing a significant amount of free energy, approximately 7 Kcal/mole. This release of energy can be used to drive the condensation reaction forward, even if it is endergonic on its own, meaning that it would not occur spontaneously under standard conditions because it requires an input of energy.
For example, the phosphorylation of glucose during glycolysis is a condensation reaction with a positive free energy change (ΔG°) of +3 Kcal/mole. By coupling this reaction with the exergonic hydrolysis of ATP, the overall free energy change of the system becomes negative. Therefore, the coupled reaction results in a ΔG° of -4 Kcal/mole, which makes the process spontaneous. This illustrates how the energy from ATP hydrolysis is used to drive metabolic processes that would otherwise be non-spontaneous.