Author Question: Suppose that the formation of a dipeptide is endergonic by +14.7 kJ/mol. If this reaction is coupled ... (Read 187 times)

bcretired · **on:** Aug 23, 2018

Suppose that the formation of a dipeptide is endergonic by +14.7 kJ/mol. If this reaction is coupled with the hydrolysis of ATP, will the net reaction be spontaneous or nonspontaneous? Explain your answer.

Question 2

Many biological reactions are endergonic. Explain how it is possible that these reactions occur spontaneously.

14vl19 · **Reply #1 on:** Aug 23, 2018

Answer to Question 1

The net reaction will be spontaneous since the Gnet value is 15.8 kJ/mol. This is based on coupling the endergonic reaction with a G of +14.7 kJ/mol with the exergonic hydrolysis of ATP with a G value of 30.5 kJ/mol. Gnet = 30.5 kJ/mol +14.7 kJ/mol = 15.8 kJ/mol.

Answer to Question 2

Endergonic reactions such as the conversion of glucose to glucose-6-phosphate are coupled with highly exergonic reactions such as the hydrolysis of ATP to ADP such that the overall reaction is exergonic and therefore spontaneous.