Learn: Osmosis in Cells (including Turgor and Plasmolysis)

Welcome!You've already learned about diffusion and cell structures, which will help you understand osmosis. Now, let's explore how water moves in and out of cells through osmosis and how this affects cells.

What is Osmosis?Osmosis is the movement of water molecules across a selectively permeable membrane from an area of high water potential to an area of low water potential. This happens to balance concentrations on both sides of the membrane.

Why is Osmosis Important?Osmosis helps cells maintain their internal environment and regulate water balance. This is essential for processes like nutrient absorption, waste removal, and maintaining cell shape.

How Osmosis Affects Plant CellsIn plant cells, osmosis causes changes in turgor pressure. When water enters, the vacuole expands, pressing against the cell wall, making the cell turgid (firm). When water leaves, the cell becomes flaccid and may undergo plasmolysis, where the cell membrane pulls away from the cell wall.

Turgor PressureTurgor pressure is the pressure exerted by water inside the vacuole on the cell wall. This pressure keeps plants upright and supports their structure.

PlasmolysisPlasmolysis occurs when a plant cell loses water due to osmosis in a solution with lower water potential than the cell. The cell membrane pulls away from the cell wall, which can damage the cell.

Osmosis in Animal CellsAnimal cells don't have cell walls, so osmosis can cause them to shrink or swell. In pure water, the cell may burst (lysis). In concentrated solutions, it shrinks (crenation).

Review Time!Great work! You've learned about osmosis, turgor pressure, and plasmolysis. Let's test your understanding with a few questions.