AQA GCSE Combined Science: Trilogy · Biology · Foundation tier
B1 — Cell biology · Transport in cells
The big idea
Osmosis is the diffusion of water from a dilute solution
(high water concentration) to a concentrated solution (low water concentration)
through a partially permeable membrane.
Watch it happen
Small water molecules slip through the membrane.
Large sugar molecules are too big to pass. The net
result: water moves into the concentrated (sugary) side.
Water molecule (small — can cross) Sugar molecule (large — cannot cross)