When plant cells are placed in salt solution their appearance is different to when they are placed in distilled water. Explain these changes.

When the plant cells are placed in the salt solution, there is a higher concentration of water molecules in the cell and a lower concentration of water in the salt solution and thus a concentration gradient has been set up. Therefore, water moves out of the cell across the partially permeable membrane by osmosis and the cell becomes flaccid as the cell membrane peels away from the cell wall. Contrastingly, when the plant cells are placed in distilled water, the concentration of water molecules is greater out of the cell than it is in the cell and therefore water moves into the cell by osmosis down the concentration gradient. The cell membrane is now pressed up against the cell wall and the cell is said to be turgid.