Water Potential

AP Water Potential Problems

1. If a plant cell’s ΨP = 2 bars and its ΨS = -3.5 bars, what is the resulting Ψ?

Ψ= -1.5

2. The plant cell from question #1 is placed in a beaker of sugar water with ΨS = -4.0 bars. In

which direction will the net flow of water be?

3. The original cell from question # 1 is placed in a beaker of sugar water with ΨS = -0.15 MPa

(megapascals). We know that 1 MPa = 10 bars. In which direction will the net flow of water be?

4. The value for Ψ in root tissue was found to be -3.3 bars. If you place the root tissue in a 0.1 M

solution of sucrose at 20°C in an open beaker, what is the Ψ of the solution, and in which

direction would the net flow of water be?

5. NaCl dissociates into 2 particles in water: Na+ and Cl-. If the solution in question 4 contained 0.1

M NaCl instead of 0.1 M sucrose, what is the Ψ of the solution, and in which direction would the

net flow of water be?

6. A plant cell with a Ψs of -7.5 bars keeps a constant volume when immersed in an open-beaker

solution that has a Ψs of -4 bars. What is the cell’s ΨP?

7. At 20°C, a plant cell containing 0.6 M glucose is in equilibrium with its surrounding solution

containing 0.5 M glucose in an open container. What is the cell’s ΨP?