The enzymes required for nitrogen fixation is:

Options

A. Nitrogen deaminase
B. Nitrodioxidasa
C. Amino acid decarboxylase
D. Nitrogenase

Answer

**Step-by-Step Text Solution:**

1. **Understanding Nitrogen Fixation**: Nitrogen fixation is the process of converting atmospheric nitrogen (N₂) into ammonia (NH₃). This process is essential for making nitrogen available to living organisms, as they cannot use atmospheric nitrogen directly.

2. **Methods of Nitrogen Fixation**: Nitrogen fixation can occur through various methods, including:
- **Natural processes**: Such as lightning or ultraviolet radiation.
- **Biological processes**: Mainly carried out by certain microorganisms.

3. **Role of Microorganisms**: The primary agents of biological nitrogen fixation are prokaryotic organisms, which include certain bacteria. These bacteria can convert atmospheric nitrogen into ammonia.

4. **Key Enzyme Involved**: The enzyme that plays a crucial role in the nitrogen fixation process is called **Nitrogenase**. This enzyme is responsible for the reduction of atmospheric nitrogen to ammonia.

5. **Types of Nitrogen-Fixing Bacteria**:
- **Symbiotic Nitrogen-Fixing Bacteria**: These bacteria, such as *Rhizobium* and *Frankia*, form symbiotic relationships with plants, particularly legumes, to fix nitrogen.
- **Free-Living Nitrogen-Fixing Bacteria**: These bacteria, such as *Anabaena* and *Nostoc*, can fix nitrogen independently without forming symbiotic relationships.

6. **Conclusion**: The enzyme required for nitrogen fixation is **Nitrogenase**. Therefore, the correct answer to the question is option number 4.

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