Question

Which of the following elements play key role in nitrogen fixation?

• A. Zinc
• B. Copper
• C. Molybdenum
• D. Manganese

Hint:

Associate nitrogen fixation with the enzyme {nitrogenase}, and remember that its active site cofactor is {FeMoco} (Iron-Molybdenum cofactor). This directly links {Molybdenum} to the process.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The question asks to identify a mineral element that is a crucial component of the enzyme responsible for biological nitrogen fixation.
Step 2: Detailed Explanation:
Biological nitrogen fixation, the conversion of \(N_2\) to \(NH_3\), is catalyzed by the enzyme complex nitrogenase.
Nitrogenase is a metalloenzyme, meaning it requires metal ions as cofactors to function. The most common form of nitrogenase contains two key metallic components:
An iron (Fe) protein.
An iron-molybdenum (Fe-Mo) protein.
The active site of the enzyme, where nitrogen is actually bound and reduced, is a complex metal cluster called the Iron-Molybdenum cofactor (FeMoco). Therefore, Molybdenum (Mo) is an essential micronutrient for nitrogen-fixing organisms. Iron (Fe) is also essential.
The other elements listed (Zinc, Copper, Manganese) are also important micronutrients for plants but are not the key components of the nitrogenase active site.
Step 3: Final Answer:
Molybdenum plays a key role in nitrogen fixation as a component of the nitrogenase enzyme.