Which is a structural polysaccharide ?

Options

A. Glycogen
B. Chitin
C. Keratin
D. Pectin.

Answer

**Step-by-Step Solution:**

1. **Understanding Structural Polysaccharides**:
- Structural polysaccharides are complex carbohydrates that provide support and rigidity to cells and tissues in organisms. They are essential for maintaining the structure of various biological entities.

2. **Identifying Examples of Structural Polysaccharides**:
- Common examples of structural polysaccharides include cellulose and chitin. Cellulose is found in the cell walls of plants, while chitin is found in the exoskeletons of arthropods and the cell walls of fungi.

3. **Analyzing the Options**:
- The options given are:
- A) Glycogen
- B) Chitin
- C) Keratin
- D) Bactin
- We need to evaluate each option to determine which one is a structural polysaccharide.

4. **Evaluating Each Option**:
- **Glycogen**: This is a storage polysaccharide found in animals and fungi, used for energy storage. Therefore, it is not a structural polysaccharide.
- **Chitin**: This is a structural polysaccharide, specifically a long-chain polymer of N-acetylglucosamine, and is a primary component of fungal cell walls and arthropod exoskeletons. This is a strong candidate.
- **Keratin**: Although it is a fibrous protein that provides structural support in animal tissues (like hair and nails), it is not classified as a polysaccharide.
- **Bactin**: This term seems to be a misspelling or confusion with "actin," which is a protein involved in muscle contraction and cell movement, not a polysaccharide.

5. **Conclusion**:
- Based on the evaluation, the only structural polysaccharide in the options provided is **Chitin (Option B)**.

**Final Answer**: B) Chitin

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