Isotonic solution describes equal concentrations outside and inside cell.

Isotonic solution describes equal concentrations outside and inside cell.

• A. Hypertonic Solution
• B. Isotonic Solution
• C. Hypotonic Solution
• D. Endocytosis

Answer: (B)

Water moves across cell membranes by osmosis to balance solute levels. When the outside solution has the same solute concentration as the inside of the cell, there is no net water movement, so the cell’s volume and shape stay stable. This state is what we call isotonic. If the outside solution is more concentrated (hypertonic), water leaves the cell and it shrinks. If it is less concentrated (hypotonic), water enters and the cell swells or may burst. Endocytosis is a process of taking in large particles by engulfing them, not about balancing solute concentrations. So equal outside and inside concentrations describe the isotonic condition.

Water moves across cell membranes by osmosis to balance solute levels. When the outside solution has the same solute concentration as the inside of the cell, there is no net water movement, so the cell’s volume and shape stay stable. This state is what we call isotonic. If the outside solution is more concentrated (hypertonic), water leaves the cell and it shrinks. If it is less concentrated (hypotonic), water enters and the cell swells or may burst. Endocytosis is a process of taking in large particles by engulfing them, not about balancing solute concentrations. So equal outside and inside concentrations describe the isotonic condition.