How many ATP are required for the formation of one molecule of `NH_3 ` by the nitrogenase enzyme ?

Options

A. Six
B. Eight
C. Twelv
D. Sixteen

Answer

To determine how many ATP molecules are required for the formation of one molecule of ammonia (NH₃) by the nitrogenase enzyme, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nitrogen Fixation**:
- Nitrogen fixation is the process by which atmospheric nitrogen (N₂) is converted into ammonia (NH₃). This process is crucial for increasing soil fertility and plant productivity.

2. **Role of Nitrogenase Enzyme**:
- The nitrogenase enzyme is responsible for catalyzing the nitrogen fixation reaction. It requires energy to facilitate this process.

3. **Energy Requirement**:
- The nitrogen fixation reaction requires a significant amount of energy, which is supplied in the form of ATP (adenosine triphosphate).

4. **Reaction Details**:
- For the conversion of nitrogen (N₂) to ammonia (NH₃), the reaction involves combining nitrogen with electrons and protons. Specifically, it requires:
- 8 electrons
- 8 hydrogen ions (H⁺)
- 16 ATP molecules

5. **Products of the Reaction**:
- The reaction produces 2 molecules of ammonia (NH₃), along with hydrogen and releases 16 ADP and 16 inorganic phosphate.

6. **Final Calculation**:
- Since the question asks for the ATP required for the formation of one molecule of ammonia, we note that 16 ATP are required to produce 2 molecules of ammonia. Therefore, for one molecule of ammonia, the ATP requirement is:
- 16 ATP / 2 = 8 ATP

### Conclusion:
- **The number of ATP required for the formation of one molecule of NH₃ by the nitrogenase enzyme is 8.**

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