Diffusion across membranes and osmosis in cells

BiologyCell BiologyAges 15–16

On the left, small molecules diffuse through membrane pores from high to low concentration until equilibrium, with particle counts on each side. On the right, a red blood cell or a plant cell sits in a hypertonic, isotonic or hypotonic solution — water osmoses in or out, causing the cell to shrink, swell, burst or plasmolyze, tracked by a volume-over-time graph.