Question

The diagram shows a normal red blood cell and a shrunken red blood cell, both of which are in salt water. In which direction did the water move to make the red blood cell shrink? Why did water move in that direction?

Answer 1

The red blood cell shrank because water moved out of the cell, which happened because the concentration of salt outside the cell was greater than the concentration of salt inside the cell. Because the salt molecules take up space in the salt water, the concentration of water outside the cell was less than the concentration of water inside the cell. Therefore, water moved out of the cell from the area of high concentration to the area of low concentration, causing the cell to shrink.

Answer 2

In the second diagram, the water moves out from the cell to the surroundings. This is because the surroundings of the cell have a higher concentration of salt than the cell. Hence, the water moves out of the cell to a higher concentration.