Water potential of a cell is lowered by the -

Options

A. Addition of solutes
B. Addition of water
C. Addition of heat
D. Removal of solutes

Answer

**Step-by-Step Solution:**

1. **Understanding Water Potential**: Water potential (Ψw) is a measure of the potential energy in water and is influenced by two main components: solute potential (Ψs) and pressure potential (Ψp). The formula for water potential is given by:
\[ Ψw = Ψs + Ψp \]

2. **Effect of Solute Addition**: When solute is added to a cell, the solute potential (Ψs) increases. Since solute potential is typically negative, an increase in solute concentration (more solute added) results in a more negative value for Ψs. This leads to a decrease in the overall water potential (Ψw) of the cell.

3. **Effect of Water Addition**: Adding water to the cell increases the water potential (Ψw) because it dilutes the solute concentration, thereby increasing the solute potential (Ψs) towards zero. This is contrary to the question, as it does not lower water potential.

4. **Effect of Heat Addition**: Increasing the temperature (adding heat) raises the kinetic energy of water molecules. This increase in kinetic energy leads to an increase in water potential (Ψw), which again does not lower it.

5. **Effect of Solute Removal**: Removing solute from the cell decreases the solute potential (Ψs), making it less negative. This results in an increase in water potential (Ψw), which is also contrary to the question.

6. **Conclusion**: The only factor that lowers the water potential of a cell is the addition of solute. Therefore, the correct answer to the question is that the water potential of a cell is lowered by the addition of solute.

**Final Answer**: Water potential of a cell is lowered by the addition of solute.

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