Advanced Placement (AP) Biology Practice Exam

What will happen to a plant cell in a hypertonic solution?

1. It will become turgid and firm

2. It will shrink due to loss of water

3. It will swell and burst

4. It will remain unchanged

The correct answer is: It will shrink due to loss of water

In a hypertonic solution, the concentration of solutes outside the plant cell is higher than that inside the cell. This difference in solute concentration causes water to move out of the cell through osmosis, a process where water molecules move from an area of lower solute concentration to an area of higher solute concentration. As water leaves the plant cell, the cell loses volume and begins to shrink. This process is known as plasmolysis. In plant cells, this results in the cell membrane pulling away from the cell wall, leading to a loss of turgor pressure which is essential for maintaining the rigidity and structure of the plant. Thus, the plant cell will shrink due to the loss of water in a hypertonic solution.