In plant cells, osmosis is involved in maintaining turgor pressure. Which statement best describes osmosis in this context?

• A. Water moves toward higher solute concentration; hypotonic environments create turgor; plasmolysis occurs in isotonic.
• B. Water moves toward lower solute concentration; hypotonic environments cause plasmolysis; turgor is unaffected.
• C. Water moves toward higher solute concentration; in plants, hypotonic environments cause turgor pressure; plasmolysis occurs in hypertonic.
• D. Water moves passively; turgor is independent of osmosis.

Answer: (A)

Osmosis moves water from a region of lower solute concentration to a region of higher solute concentration. In plant cells, water entering from a hypotonic environment fills the vacuole, pushes against the cell wall, and creates turgor pressure that helps keep the plant upright. If the surrounding solution is hypertonic, water leaves the cell, causing plasmolysis and a loss of turgor. In an isotonic solution there is no net water movement and turgor is not maintained. So the best description is that water moves toward higher solute concentration; hypotonic environments create turgor; plasmolysis occurs in hypertonic environments.