Selective permeability occurs in

Options

A. Cell wall
B. Plasma membrane
C. Cytoplasm
D. None of these

Answer

**Step-by-Step Solution:**

1. **Understanding Selective Permeability:**
- Selective permeability refers to the ability of a membrane to allow certain substances to pass through while restricting others. This means that the membrane selectively allows some molecules to enter or exit the cell based on specific criteria.

2. **Identifying the Membranes:**
- The question provides four options: cell wall, plasma membrane, cytoplasm, or none of these. We need to evaluate which of these structures exhibits selective permeability.

3. **Analyzing Each Option:**
- **Cell Wall:**
- The cell wall is a rigid structure found in plant cells, fungi, and some bacteria. It provides support and protection but is generally not selective; it allows most substances to pass freely.
- **Plasma Membrane:**
- The plasma membrane, also known as the cell membrane, is a phospholipid bilayer that surrounds the cell. It is known for its selective permeability, allowing certain molecules (like water and nutrients) to pass while restricting others (like large molecules and ions).
- **Cytoplasm:**
- The cytoplasm is the jelly-like substance inside the cell where organelles are located. It does not function as a barrier for selective permeability.
- **None of These:**
- This option suggests that none of the provided structures exhibit selective permeability, which is incorrect based on our analysis.

4. **Conclusion:**
- Based on the analysis, the plasma membrane is the structure that exhibits selective permeability. It allows solvent molecules to pass through while selectively allowing only certain solute molecules that the cell requires.

5. **Final Answer:**
- The correct answer is the **plasma membrane**.

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