Nitrogen fixing enzyme in root nodule is

Options

A. nitrase
B. nitrogenase
C. nitrosomonas
D. nitrogen esterase

Answer

To answer the question about the nitrogen-fixing enzyme in root nodules, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Context**: Understand that the question is about nitrogen fixation, which is a crucial process for converting atmospheric nitrogen into a usable form for plants.

2. **Recognize the Location**: Nitrogen fixation occurs in the root nodules of leguminous plants. These nodules are formed in symbiosis with nitrogen-fixing bacteria, primarily Rhizobium.

3. **Determine the Enzyme**: The enzyme responsible for nitrogen fixation in these root nodules is called **nitrogenase**. This enzyme catalyzes the conversion of atmospheric nitrogen (N₂) into ammonia (NH₃), which can then be utilized by plants.

4. **Clarify Misconceptions**: It is important to note that while other terms like "nitrosomonas" and "nitrogen esterase" may be mentioned, they are not the enzymes responsible for nitrogen fixation in root nodules.

5. **Conclude**: Therefore, the nitrogen-fixing enzyme in root nodules is **nitrogenase**.

### Final Answer:
The nitrogen-fixing enzyme in root nodules is **nitrogenase**.

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