The value of osmotic pressure becomes equal to diffusion pressure deficit when a cell is placed in a

Options

A. hypertonic solution
B. hypotonic solution
C. isotonic solution
D. both (2) and (3)

Answer

**Step-by-Step Solution:**

1. **Understanding Osmotic Pressure and Diffusion Pressure Deficit:**
- Osmotic pressure is the pressure required to prevent the flow of water across a semipermeable membrane due to osmosis. It is directly related to the concentration of solutes in a solution.
- Diffusion pressure deficit (DPD) is the difference between the osmotic pressure of the cell sap and the pressure potential. It indicates the tendency of water to move into the cell.

2. **Analyzing the Types of Solutions:**
- **Hypertonic Solution:** This solution has a higher concentration of solutes compared to the cell sap. When a cell is placed in a hypertonic solution, water moves out of the cell to the solution, leading to cell shrinkage.
- **Hypotonic Solution:** This solution has a lower concentration of solutes compared to the cell sap. In this case, water moves into the cell from the solution, causing the cell to swell.
- **Isotonic Solution:** This solution has an equal concentration of solutes compared to the cell sap. There is no net movement of water, and the cell remains unchanged.

3. **Determining When Osmotic Pressure Equals DPD:**
- In a hypertonic solution, the osmotic pressure of the solution is greater than that of the cell sap, leading to water leaving the cell. The DPD will be high because water is moving out.
- In a hypotonic solution, the osmotic pressure of the cell sap is greater, causing water to enter the cell, which does not satisfy the condition where osmotic pressure equals DPD.
- In an isotonic solution, osmotic pressure and DPD are balanced, but the question specifically asks for a scenario where they are equal due to the movement of water.

4. **Conclusion:**
- The value of osmotic pressure becomes equal to the diffusion pressure deficit when a cell is placed in a hypertonic solution. Therefore, the correct answer is the first option: **hypertonic solution**.

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