IGCSE Biology glossary
Turgor
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Definition
The state of a plant cell when it has absorbed water by osmosis and the cytoplasm pushes outwards against the cell wall. The cell wall prevents the cell from bursting and the cell is described as turgid. Turgor pressure helps support the plant and keeps stems and leaves rigid.
What to include in an exam answer
Turgor explains why plants wilt: when cells lose water and become flaccid, they lose turgor pressure and the plant droops. Always link turgor to the cell wall providing resistance.
Example in context
Explain why a plant stem becomes floppy when the soil is dry (3 marks): Water is lost from cells by osmosis because the water potential outside the cell is lower. The cells become flaccid and lose turgor pressure. Without turgor pressure pushing against the cell walls, the stem loses its rigidity and wilts.
Related syllabus topic
Movement into & out of cells