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Plasmolysis and deplasmolysis: The cell membrane of a plant cell is selectively permeable. Water can pass through it, while dissolved sodium and chloride ions are not let through in this model. In a hypertonic external medium, the cell releases water on balance; the vacuole and protoplast shrink. In a hypotonic external medium, the cell takes up water on balance and becomes turgid.
Substance and particle level: The microscopic field of view shows the observable change of the whole cell. The separate particle window explains this change using randomly moving water particles, ions and a phospholipid bilayer.
Tasks:
- Compare the plant cell after adding a hypotonic, isotonic and hypertonic medium.
- Describe the water flow in the particle model.
- Explain the connection between ion concentration, osmosis and the state of the cell.