IGCSE›Cambridge IGCSE Biology›Mind mapsOsmosisCambridge IGCSE Biology: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsDefinitionNet movement of water from higher to lower water potentialThrough a partially permeable membraneDilute solution has higher water potentialPassive: no energy neededInto and outOutside more dilute: water goes inOutside more concentrated: water goes outWater moves both ways, with a net directionNet movement stops at equal water potentialPlant cellsTurgid: firm, membrane presses on cell wallFlaccid: turgor lost, tissue limpPlasmolysed: membrane pulls away from wallTurgor pressure gives supportOsmosiswater across membranesDialysis tubingTubing models a partially permeable membraneSugar solution inside, distilled water outsideTubing gains mass as water entersBlot dry before each weighingIn organismsRoot cells take up soil waterKidneys reabsorb water by osmosisWater is the solvent for digestion and transportExam tipsSay water potential, not concentrationOnly water moves, sugar cannot passPlasmolysis: membrane pulls away from wall