IGCSE Biology glossary
Plasmolysis
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Definition
The shrinkage of a plant cell's cytoplasm away from the cell wall when the cell is placed in a concentrated solution. Water leaves the vacuole and cytoplasm by osmosis, causing the cell membrane to pull away from the cell wall.
What to include in an exam answer
Plasmolysis only occurs in plant cells. The cell membrane pulls away from the cell wall but the cell does not burst or change external shape because the cell wall remains intact.
Example in context
Describe and explain what happens to a plant cell placed in a concentrated salt solution (3 marks): Water moves out of the cell by osmosis because the water potential outside is lower than inside. The vacuole shrinks and the cell membrane pulls away from the cell wall. This is plasmolysis.
Related syllabus topic
Movement into & out of cells