Diffusion across the cell membrane
A channel protein (open and closed)
A carrier protein changing shape during facilitated diffusion
Osmosis and the partially permeable membrane
How osmosis works.
The water moves from the region of higher water potential (dilute solution) to the region of lower water potential (concentrated solution).
Remember – the movement of molecules from high concentration to low concentration is diffusion. If this movement requires the aid of a protein (for example because the molecule is charged and cannot pass directly through the phospholipid bilayer) this is facilitated diffusion.
Voltage-gated potassium channels facilitate the diffusion of potassium ions
Effect of osmosis on animal cells