Heterocysts present in Nostoc are specialsed for

Options

A. Fragmentation
B. Nitrogen fixation
C. Storage
D. Photosynthesis.

Answer

To answer the question about the function of heterocysts in Nostoc, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the organism**: Nostoc is classified as a blue-green algae, also known as cyanobacteria. This classification is important because it helps us understand its biological functions.

2. **Understand the role of nitrogen fixation**: Nitrogen fixation is the process of converting atmospheric nitrogen (N2) into ammonia (NH3), which can be utilized by plants. This is crucial because plants cannot use atmospheric nitrogen directly.

3. **Recognize the function of heterocysts**: Heterocysts are specialized cells found in certain cyanobacteria, including Nostoc. Their primary function is to facilitate nitrogen fixation.

4. **Explain the mechanism**: Heterocysts contain the enzyme nitrogenase, which is essential for the conversion of N2 to NH3. However, nitrogenase is sensitive to oxygen and gets deactivated in its presence. Heterocysts create a micro-anaerobic environment that protects nitrogenase from oxygen, allowing nitrogen fixation to occur.

5. **Evaluate the options**: Given the options:
- Option 1: Fragmentation - Incorrect
- Option 2: Nitrogen fixation - Correct
- Option 3: Storage - Incorrect
- Option 4: Photosynthesis - Incorrect

The correct answer is that heterocysts in Nostoc are specialized for nitrogen fixation.

### Final Answer:
Heterocysts present in Nostoc are specialized for nitrogen fixation.

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