Movement across cell membranes

By the end you’ll be able to

• Define diffusion as the net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient, and explain it using the particle model.
• Explain how factors such as concentration gradient, temperature, surface area, membrane thickness and diffusion distance affect the rate of diffusion.
• Describe osmosis as the net movement of water molecules through a partially permeable membrane from a dilute solution to a more concentrated solution.