Question

If by radiation all nitrogenase enzyme is inactivated, then there will be no

• A. Fixation of nitrogen in legumes
• B. Fixation of atmospheric nitrogen
• C. Conversion from nitrate to nitrite in legumes
• D. Conversion from ammonium to nitrate in soil

Answer 1

Answer: (A)

Fixation of nitrogen in legumes

Answer 2

The process by which N2 is reduced to NH4+ is called nitrogen fixation. Nitrogenase enzyme catalyzes this reduction. It is only carried out by prokaryotic microorganisms. Principal N2-fixers include certain free living cyanobacteria in symbiotic associations with fungi in lichens or with ferns, mosses, and liverworts, and by bacteria or other microbes associated symbiotically with roots, especially those of legumes. About 15 percent of the nearly 20,000 species in the fabaceae (Leguminosae) family have been examined for N2 fixation, and approximately 90 percent of these have root nodules in which fixation occurs. So without active nitrogenase enzyme there will be no N, fixation in legumes.