diffusion

Question 1

What is diffusion

Answer 1

-Diffusion is the net movement of particles down a concentration gradient: from a region of high concentration to a region of low concentration.
-Passive process as no energy required

Question 2

What are factors affecting simple diffusion

Answer 2

-Concentration gradient
-Membrane thickness
-Surface area
-Temperature

Question 3

What is facilitated diffusion

Answer 3

-Larger molecules and ions would move slowly through the membrane so they need to diffuse through specialised carrier or channel proteins
-Still a passive process

Question 4

What is faster simple or facilitated diffusion

Answer 4

-Facilitated diffusion

Question 5

Details of facilitated diffusion through carrier proteins

Answer 5

-Large molecule attaches to carrier protein.
-This causes protein to change shape, releasing molecule to other side of membrane.
-Different carrier proteins needed for different shaped molecules.

Question 6

Details of facilitated diffusion through channel proteins

Answer 6

-Form pores in the membrane allowing charged molecules to move through.
-Different channel proteins needed for different charged particles.

Question 7

Factors affecting facilitated diffusion

Answer 7

-Concentration gradient
-Number of channel,carrier proteins