Facilitated Diffusion
What is facilitated diffusion?
• Facilitated diffusion is a passive form of
transport meaning no energy or ATP is used by
the cell.
• In facilitated diffusion large molecules move
through a cell membrane down their
concentration gradient (move from a high
concentration to a low concentration) by
means of protein channels.
•The cell membrane is a semi-permeable
membrane that contains the contents of
the cell.
protein channels
• protein channels are parts of the cell
membrane that assist certain ions to move
into and out of the cell.
protein channels
• protein channels are needed when a
substance cannot pass through the cell
membrane on its own. Protein channels
provide a passageway for these substances to
move in and out of the cell almost like a
tunnel.
• Glucose, Sodium and Chloride are common
substances that require the use of protein
channels or carrier proteins.