Question

For Its action, nitrogenase requires?

• A. High input of energy
• B. ${\mathrm{Mn}}^{2+}$
• C. Super oxygen radicals
• D. Light

Answer 1

The correct option is A

High input of energy

The correct option is option A.

Explanation for correct option:

1. Nitrogenase is the enzyme produced by cyanobacteria and rhizobacteria.
2. It reduces nitrogen to ammonia, which is a process of nitrogen fixation.
3. This enzyme is active in anaerobic conditions.
4. It carries out nitrogen fixation using high input of energy.
5. When Ammonia$\left({\mathrm{NH}}_3\right)$ reacts with Oxygen$\left({\mathrm{O}}_2\right)$ in presence of the enzyme Nitrate reductase it gives Nitrite$\left({\mathrm{NO}}_2^{-}\right)$ along with water$\left({\mathrm{H}}_2\mathrm{O}\right)$ and two molecules of the proton$\left({\mathrm{H}}^{+}\right)$.

$\underset{\left(\mathrm{Ammonia}\right)}{2{\mathrm{NH}}_3\left(\mathrm{g}\right)}+\underset{\left(\mathrm{Oxygen}\right)}{3{\mathrm{O}}_2\left(\mathrm{g}\right)}\stackrel{\mathrm{Nitrate}\mathrm{Reductase}}{\to }2\underset{\left(\mathrm{Nitrite}\right)}{{\mathrm{NO}}_2^{-}\left(\mathrm{g}\right)}+\underset{\left(\mathrm{Water}\right)}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}+\underset{\left(\mathrm{Proton}\right)}{2{\mathrm{H}}^{+}}$

Explanation for incorrect options:

Option B:

1. Manganese$\left({\mathrm{Mn}}^{2+}\right)$ is not used for the biosynthesis of nitrogenase or glutamine synthetase.
2. Manganese is used for in-vitro activation of Nitrogenase from nitrogen and glutamate growth.

Option C:

1. Superoxygen radicals inhibit the production of nitrogenase.
2. Nitrogen fixation happens in cyanobacteria where oxygen is less in heterocysts.

Option D:

1. Nitrogenase strictly depends on light.
2. However, stability of Nitrogenase can be attained by suspension of light instead of continuous light during the day.

Final Answer: For its Action, nitrogenase requires a high input of energy,