chapter 5.3 - Diffusion

Question 1

What is Diffusion?

Answer 1

Diffusion is the net movement of particles from a region of high concentration to a region of low concentration, along a concentration gradient.

Question 2

What are the factors affecting rate of diffusion without a membrane? (simple diffusion)

Answer 2

• Temperature - higher temp increases KE

- concentration difference - the greater the difference in conc. between two regions the faster the rate of diffusion.

Question 3

What are the factors affecting rate of diffusion with a membrane?

Answer 3

• Surface Area - the higher the SA, the higher the rate of diffusion.
• Membrane thickness - the thicker the membrane, the more distance the particle has to travel and the slower the rate of diffusion.

Question 4

What is Facilitated Diffusion?

Answer 4

When polar molecules and ions pass through protein channels or carrier proteins across a membrane, and does not require energy to complete.

Question 5

What is the rate of facilitated diffusion dependant on?

Answer 5

• Temperature
• concentration gradient
• membrane surface area
• thickness of membrane
• number of protein channels present