Which term refers to a solution with higher solute concentration outside the cell, causing water to move out?

Which term refers to a solution with higher solute concentration outside the cell, causing water to move out?

• A. Hypertonic
• B. Hydrostatic Pressure
• C. Isotonic
• D. Hypotonic

Answer: (A)

High solute outside means the outside solution is hypertonic relative to the cell. Water moves by osmosis from the inside to the outside to balance solute concentrations, so the cell loses water and shrinks. If the outside were isotonic, there would be no net water movement; if it were hypotonic, water would move into the cell and it would swell. Hydrostatic pressure is about fluid pressure, not solute balance, so it doesn’t explain this net water movement.

High solute outside means the outside solution is hypertonic relative to the cell. Water moves by osmosis from the inside to the outside to balance solute concentrations, so the cell loses water and shrinks. If the outside were isotonic, there would be no net water movement; if it were hypotonic, water would move into the cell and it would swell. Hydrostatic pressure is about fluid pressure, not solute balance, so it doesn’t explain this net water movement.