The Cell Membrane

Journey inside the cell to see how the cell membrane acts as both a barrier and an entrance. How does it take in nutrients while keeping out potentially damaging molecules? Biology - Cells And DNA - Learning Points. The cell membrane protects the cell contents from their environment and controls the entry and exit of substances. Diffusion is when particles move from an area of high to low concentration. The diffusion of water across a selectively permeable membrane from high to low concentration is called osmosis. The transport of molecules across the cell membrane is a vital process. A Twig Context Film. Reinforce and extend the learning required by the curriculum. Twig’s context films show abstract concepts in action in the real world.