Question

When a cell is placed in a hypertonic solution:
A) Solute exits the cell to equalize the concentration on both sides of the membrane
B) Water exits the cell toward the area of lower solute concentration
C) Water exits the cell toward the area of higher solute concentration
D) Solute exits and water enters the cell

Answer 1

Hint: A hypertonic solution is a solution that has a higher solute concentration outside the cell than inside. A normal cell kept in a salt solution or sugar solution is a perfect example of hypertonic solution.

Step by step explanation
Option A: Solute exits the cell to equalize the concentration on both sides of the membrane—In an isotonic solution the solute potential and water potential on both the side of the semi permeable membrane will be equal. If not water exits out either from the cell or enters into the cell to maintain the osmoregularity.
Option B: Water exits the cell toward the area of lower solute concentration – In The process osmosis usually water molecules move from an area of high-water potential or low solute potential to an area of low water potential or high solute potential.
Option C: Water exits the cell toward the area of higher solute concentration - If a cell is placed in a hypertonic solution, the cell is considered hypotonic. In this condition water molecules move from an area of high water potential or low solute potential to an area of low water potential or high solute potential.
Option D: Solute exits and water enters the cell—in the process osmosis it is not the solute molecules that are in motion but the water molecules. Water molecules move from an area of high-water potential or low solute potential to an area of low water potential or high solute potential.

So the correct answer is option C.

Note:
Solute potential and Water potential are two factors that determine the direction of flow of water molecules in a cell when kept in a solution. Water potential is the potential energy of water per unit volume. Solute potential is directly proportional to the number of solutes in the solution.