Which plant nutrient is a component of enzyme nitrogenase and plays an important role in nitrogen metabolism ?

Options

A. Magnesium
B. Molybdenum
C. Potassium
D. Phosphorus

Answer

To answer the question regarding which plant nutrient is a component of the enzyme nitrogenase and plays an important role in nitrogen metabolism, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of Nitrogenase**:
- Nitrogenase is an enzyme that facilitates the process of nitrogen fixation, which is the conversion of atmospheric nitrogen (N₂) into ammonia (NH₃). This process is crucial for making nitrogen available to plants and other organisms.

2. **Identify the Components of Nitrogenase**:
- Nitrogenase is a complex enzyme that requires specific metal ions to function. The primary metal ions associated with nitrogenase include molybdenum and iron.

3. **Recognize the Importance of Molybdenum**:
- Molybdenum is a key component of nitrogenase. It plays a critical role in the enzyme's ability to catalyze the reduction of nitrogen gas to ammonia.

4. **Consider Other Nutrients**:
- While other nutrients like magnesium, potassium, and phosphorus are important for various plant functions (e.g., magnesium in chlorophyll, potassium in nutrient transport, phosphorus in DNA synthesis), they are not directly involved in nitrogenase activity.

5. **Conclude the Answer**:
- Given that molybdenum is essential for the functioning of nitrogenase and plays a significant role in nitrogen metabolism, the correct answer to the question is **molybdenum**.

### Final Answer:
The plant nutrient that is a component of the enzyme nitrogenase and plays an important role in nitrogen metabolism is **molybdenum**.

---