Osmosis = movement of water molecules, across a partially permeable membrane, from a region of high concentration of water to a low concentration of water molecules.
It allows plants to take in water through their roots.
It is used in kidney dialysis machines to filter the blood.
Partially Permeable Membrane
Small molecules, such as water can pass through the small holes in the membrane. But larger molecules like sugar cannot pass through the membrane.
Diffusion = movement of molecules, from a region of high concentration to a region of low concentration.
Oxygen diffuses into cells, and the waste carbon dioxide diffuses out.
This video looks at diffusion in living cells