Ammonia synthesis by nitrogenase requires

Options

A. high input of energy
B. super oxygen radical
C. `Mn^(2+)`
D. none of these

Explanation

To solve the question "Ammonia synthesis by nitrogenase requires", we can follow these steps:

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

### Step 2: Identify the Enzyme Involved
- The enzyme responsible for this conversion is called nitrogenase. Only certain prokaryotic organisms, known as nitrogen-fixers, possess this enzyme.

### Step 3: Determine the Energy Requirement
- The nitrogenase enzyme requires a significant amount of energy to catalyze the reaction. Specifically, it requires around 8 ATP molecules for the synthesis of each ammonia molecule.

### Step 4: Analyze the Options Given
- The options provided are:
1. High input of energy
2. Super oxygen radical
3. Mn2 plus
4. None of this

### Step 5: Select the Correct Option
- Based on the understanding that nitrogenase requires a high input of energy (in the form of ATP) to synthesize ammonia, the correct answer is:
- **Option 1: High input of energy**

### Final Answer
Ammonia synthesis by nitrogenase requires **high input of energy**.

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