Select the incorrect statement regarding nitrogen metabolism:

Options

A. Mo and Fe are the components of nitrogenase enzyme
B. LHb is formed by contribution of both plant and bacteria.
C. LHb protects the nitrogenase enzyme by binding to `O_(2)`
D. `N_(2)` fixation is a passive process

Answer

To determine the incorrect statement regarding nitrogen metabolism, we can analyze the provided information step by step:

### Step 1: Understand Nitrogen Fixation
Nitrogen fixation is the process of converting atmospheric nitrogen (N2) into ammonia (NH3). This process is crucial for making nitrogen available to living organisms.

**Hint:** Remember that nitrogen fixation is essential for converting inert atmospheric nitrogen into a usable form for plants.

### Step 2: Identify the Role of Nitrogenase
The enzyme nitrogenase plays a key role in nitrogen fixation. It catalyzes the conversion of nitrogen gas into ammonia. This process requires energy in the form of ATP and involves the reduction of nitrogen.

**Hint:** Focus on the importance of nitrogenase and the energy requirements for nitrogen fixation.

### Step 3: Examine the Role of Leg Hemoglobin (LHB)
Leg hemoglobin (LHB) is produced in leguminous plants and helps to protect nitrogenase from oxygen. It binds to oxygen, thus creating an anaerobic environment that is favorable for nitrogen fixation.

**Hint:** Consider how LHB functions as an oxygen scavenger to support nitrogenase activity.

### Step 4: Evaluate the Statements
1. **Statement about nitrogen fixation and nitrogenase**: True statement.
2. **Statement about LHB**: True statement.
3. **Statement claiming nitrogen fixation is a passive process**: This is the incorrect statement. Nitrogen fixation is an active process that requires energy (ATP).

**Hint:** Look for statements that contradict the known facts about nitrogen metabolism.

### Step 5: Conclusion
The incorrect statement regarding nitrogen metabolism is that nitrogen fixation is a passive process. In reality, it is an active process that requires significant energy input.

**Final Answer:** The incorrect statement is that nitrogen fixation is a passive process.