A plant cell placed in a solution with a higher water potential will

Step 1: Analyze the question The question asks what happens to a plant cell placed in a solution that has a higher water potential than the cell's own contents. In other words, the solution is hypotonic (more dilute) compared with the cell sap.

Step 2: Explain the concept

• Water moves by osmosis from a region of higher water potential to a region of lower water potential, across a partially permeable membrane.
• If the surrounding solution has a higher water potential than the cell sap, water moves into the cell.
• As water enters, the vacuole swells and pushes the cytoplasm and cell membrane against the cell wall. The cell becomes firm, or turgid.
• Unlike an animal cell, a plant cell has a strong, rigid cellulose cell wall. It resists further expansion, so it does not burst. Pressure builds up inside (turgor pressure) until it balances the water's tendency to enter.

Step 3: Evaluate the options

• A. Expand and then shrink: wrong. There is no reason for water to leave afterward.
• B. Enlarge and become turgid: correct. Water enters, and the cell swells slightly and becomes turgid.
• C. Expand and then burst: wrong. This happens to animal cells (such as red blood cells), not plant cells, because of the cell wall.
• D. Decrease in size and become flaccid: wrong. This happens in a solution with a lower water potential (hypertonic), where water leaves the cell.

Step 4: Answer The plant cell takes in water by osmosis, enlarges slightly, and becomes turgid.

Exam tip: Remember "Plant cells don't burst, they get turgid."

• Higher water potential outside → water in → turgid
• Lower water potential outside → water out → flaccid, then plasmolysed if the loss continues