The involvement of ATP in the nitrogenase complex is because ATP is needed to: a. provide electrons. b. phosphorylate the enzyme. c. break the N2 triple bond. d. transfer electrons from ferredoxin. e. all are true.

c. break the N2 triple bond.

Explanation:

In the general nitrogen reduction reaction (which occurs in the nitrogenase complex), ferredoxin acts as an electron donor to Fe-protein, which in turn hydrolyzes ATP and reduces MoFe-protein. By reducing MoFe-protein one can then reduce numerous (triple bonded) substrates although, under natural conditions, it reacts only to N2 and H +.

That is, ATP must be present in the reaction so that MoFe-protein can break the triple bond N2.

The binding and hydrolysis of ATP to Fe-protein causes a change in conformation of this protein which facilitates redox reactions. The enzymatic reduction of N2 by nitrogenase requires a large energy investment, although the exact changes in free energy are still unknown.