Water potential of a cell when it is placed in hypertonic solution :

Options

A. Decreases
B. Increases
C. First increases then decreases
D. No change

Answer

**Step-by-Step Solution:**

1. **Understanding Water Potential**: Water potential (Ψ) is defined as the potential energy of water in a system compared to pure water, where it is assigned a value of zero. It is influenced by solute concentration and pressure.

2. **Identifying Hypertonic Solution**: A hypertonic solution has a higher concentration of solutes compared to the inside of the cell. This means that the water potential outside the cell is lower than that inside the cell.

3. **Movement of Water**: When a cell is placed in a hypertonic solution, water moves out of the cell into the surrounding solution. This process is known as exosmosis.

4. **Effect on Water Potential**: As water leaves the cell, the number of water molecules inside the cell decreases. Since water potential is dependent on the number of water molecules, a decrease in water molecules leads to a decrease in water potential.

5. **Conclusion**: Therefore, when a cell is placed in a hypertonic solution, the water potential of the cell decreases due to the loss of water through exosmosis.

**Final Answer**: The water potential of a cell when it is placed in a hypertonic solution decreases.

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