‘Porins’ are chemically

Options

A. Phospholipids
B. Carbohydrates
C. Proteins
D. Glycolipids

Answer

**Step-by-Step Text Solution:**

1. **Understanding Porins**: Porins are specialized proteins that form channels in the membranes of cells. They are crucial for the transport of molecules across the membrane.

2. **Identifying the Chemical Nature**: The question asks for the chemical classification of porins. We need to analyze the options provided:
- Option 1: Phospholipids
- Option 2: Carbohydrates
- Option 3: Proteins
- Option 4: Glycolipids

3. **Analyzing the Options**:
- **Phospholipids**: These are major components of cell membranes but do not function as pores.
- **Carbohydrates**: These are primarily involved in energy storage and structural functions, not as membrane channels.
- **Proteins**: Porins are indeed proteins that form beta-barrel structures to create pores in the membrane.
- **Glycolipids**: These are lipids with carbohydrate groups attached, mainly involved in cell recognition and signaling, not in forming pores.

4. **Conclusion**: Based on the analysis, the correct classification of porins is that they are proteins. Therefore, the answer is option 3: proteins.

**Final Answer**: Porins are chemically proteins (Option 3).

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