Which enzyme specifically occurs in Heterocyst of blue green Algae :–

Options

A. Cytochrome oxidase
B. Nitrogenase
C. Zymase
D. Peptidyl transferase

Answer

To answer the question regarding which enzyme specifically occurs in the heterocyst of blue-green algae, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Heterocyst**:
- Heterocysts are specialized cells found in certain blue-green algae (cyanobacteria) that are involved in nitrogen fixation. They have a thick, transparent wall and are positioned intermittently along the filament of the algae.

**Hint**: Remember that heterocysts are unique structures in blue-green algae that play a crucial role in nitrogen fixation.

2. **Identifying the Function of Heterocyst**:
- The primary function of heterocysts is to facilitate the conversion of atmospheric nitrogen (N₂) into ammonia (NH₃), a process known as nitrogen fixation. This is essential for the growth of the algae, as nitrogen is a vital nutrient.

**Hint**: Focus on the role of heterocysts in nitrogen fixation to narrow down the enzyme options.

3. **Analyzing the Enzyme Options**:
- The options given are:
- Cytochrome oxidase
- Nitrogenase
- Zymase
- Peptidyl transferase
- Among these, we need to identify which enzyme is specifically associated with the nitrogen fixation process in heterocysts.

**Hint**: Consider which enzyme is known for its role in nitrogen fixation.

4. **Identifying the Correct Enzyme**:
- Nitrogenase is the enzyme responsible for catalyzing the reduction of nitrogen gas to ammonia. It is a multi-subunit enzyme complex that contains iron, sulfur, and molybdenum. This enzyme is specifically found in heterocysts, making it the correct answer.

**Hint**: Recall that nitrogenase is crucial for nitrogen fixation and is specifically found in heterocysts.

5. **Conclusion**:
- Based on the analysis, the enzyme that specifically occurs in the heterocyst of blue-green algae is **Nitrogenase**.

**Final Answer**: Nitrogenase (Option 2).