The shrinkage of the protoplasm away from the cell wall due to exosmosis.
Explanation
Plasmolysis is a specific physiological phenomenon observed in plant cells when they are placed in a hypertonic solution. It is governed by the principles of osmosis and the structural properties of the plant cell wall versus the plasma membrane.
- The bursting of a cell when placed in a hypotonic solution. is incorrect: When a cell is placed in a hypotonic solution (lower solute concentration outside), water enters the cell via endosmosis. In animal cells, this can lead to bursting (cytolysis). In plant cells, the rigid cell wall prevents bursting, causing the cell to become turgid.
- The shrinkage of the protoplasm away from the cell wall due to exosmosis. is correct: Plasmolysis occurs when a plant cell is placed in a hypertonic solution (higher solute concentration outside). Water moves out of the cell through exosmosis to balance the concentration gradient. Consequently, the turgor pressure decreases, and the protoplasm (cytoplasm + plasma membrane) shrinks and detaches from the rigid cell wall.
- The breakdown of the plasma membrane by lysosomal enzymes. is incorrect: The breakdown of cellular components by lysosomal enzymes is generally referred to as autolysis or intracellular digestion, which is unrelated to osmotic water movement.
- The division of the cytoplasm during the final stage of cell division. is incorrect: The division of the cytoplasm following nuclear division (karyokinesis) is termed cytokinesis.
Key Takeaway: Plasmolysis is the shrinkage of the protoplast from the cell wall caused by exosmosis when a plant cell is exposed to a hypertonic environment.