Question

Control over nitrogenase activity is accomplished by which of the following?

a. ATP serves as an allosteric activator
b. AMP serves as an allosteric inhibitor
c. NH4+ prevents expression of the genes that encode nitrogenase
d. phosphorylation prevents activity
e. none of the above

Answer 1

C

Step-by-step explanation:

Control over nitrogenase activity is accomplished by NH4+ prevents expression of the genes that encode nitrogenas.

Nitrogenase synthesis in free-living N2-fixing bacteria is universally under repressor control by ammonia. This, however, is not

the case for rhizobia. A need for N2 as inducer apparently does not

exist. The degree of ammonia repression is unusual in its strength.

Nitrogenase activity is at least 1O,OOO-fold lower in extracts of

NH4+-grown cells versus N2-grown cells.