Facilitated diffusion

• Movement across membranes by facilitated diffusion involves factors such as surface area, concentration gradients, and the number of channel/carrier proteins.
• Facilitated diffusion is a process where larger/polar molecules like glucose move across a selectively permeable membrane down a concentration gradient through a channel/carrier protein, requiring no ATP/energy.
• Factors affecting the rate of facilitated diffusion include surface area, concentration gradients, and the number of channel/carrier proteins.
• Carrier proteins transport large molecules, changing shape when the molecule attaches.
• Channel proteins transport charged/polar molecules through its pore, some are gated so can open/close.
• Different carrier and channel proteins facilitate the diffusion of different specific molecules.