Which statement best describes isotonic solutions in relation to cells?

Which statement best describes isotonic solutions in relation to cells?

• A. Water Moves Into The Cell
• B. Water Moves Out Of The Cell
• C. The Solute Concentration Outside Equals The Solute Concentration Inside The Cell, Resulting In No Net Water Movement
• D. The Cell Will Always Swell

Answer: (C)

In isotonic conditions, the solute concentration outside the cell matches the inside, so there’s no net water movement across the membrane. Water may still cross, but it moves in and out at equal rates, keeping the cell’s volume stable. That’s why this option is the best: it captures the idea that there’s no net change in water flow when solute levels are equal on both sides. If the outside were less concentrated (hypotonic), water would enter the cell and it would swell. If the outside were more concentrated (hypertonic), water would leave the cell and it would shrink. The statement about the cell always swelling describes a hypotonic scenario, not isotonic.

In isotonic conditions, the solute concentration outside the cell matches the inside, so there’s no net water movement across the membrane. Water may still cross, but it moves in and out at equal rates, keeping the cell’s volume stable. That’s why this option is the best: it captures the idea that there’s no net change in water flow when solute levels are equal on both sides.

If the outside were less concentrated (hypotonic), water would enter the cell and it would swell. If the outside were more concentrated (hypertonic), water would leave the cell and it would shrink. The statement about the cell always swelling describes a hypotonic scenario, not isotonic.