If the external solution has a lower solute concentration than the cell interior, the solution is called

If the external solution has a lower solute concentration than the cell interior, the solution is called

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

Answer: (B)

The concept being tested is tonicity and osmosis. When the solution outside the cell has a lower solute concentration than the fluid inside the cell, the outside is hypotonic relative to the cell. Water moves into the cell to balance solute concentrations, increasing internal water potential and causing the cell to swell. In animal cells this can lead to bursting, while plant cells resist swelling due to the cell wall and end up turgid. Hypertonic would mean more solute outside than inside, causing water to leave the cell. Isotonic means equal solute concentrations on both sides, so no net water movement. Osmotic pressure refers to the pressure exerted by the movement of water due to osmosis, not a description of a solution’s tonicity.

The concept being tested is tonicity and osmosis. When the solution outside the cell has a lower solute concentration than the fluid inside the cell, the outside is hypotonic relative to the cell. Water moves into the cell to balance solute concentrations, increasing internal water potential and causing the cell to swell. In animal cells this can lead to bursting, while plant cells resist swelling due to the cell wall and end up turgid.

Hypertonic would mean more solute outside than inside, causing water to leave the cell. Isotonic means equal solute concentrations on both sides, so no net water movement. Osmotic pressure refers to the pressure exerted by the movement of water due to osmosis, not a description of a solution’s tonicity.