In plant cells, plasmolysis occurs in which environment?

• A. Isotonic
• B. Hypotonic
• C. Hypertonic
• D. Equi-tonic

Answer: (C)

Plasmolysis happens when a plant cell is placed in a hypertonic environment, meaning the outside solution has a higher solute concentration than the cell’s interior. Water moves out by osmosis, the cytoplasm shrinks, and the plasma membrane pulls away from the cell wall. This loss of water lowers turgor pressure and causes the cell to appear wilted or shrunken. In isotonic conditions there’s no net water movement, so plasmolysis doesn’t occur. In hypotonic conditions, water enters the cell, increasing turgor pressure and making the cell turgid rather than plasmolyzed. Equi-tonic is another term for isotonic, which also wouldn’t cause plasmolysis.