Diffusion 2B

Question 1

Define diffusion

Answer 1

Movement of particles from a higher concentration to a lower concentration

Question 2

Which ways do particles move

Answer 2

Both directions but the net movement is to a lower concentration. Particles will move down a concentration gradient

Question 3

What type of process is simple diffusion

Answer 3

A passive process

Question 4

Define facilitated diffusion

Answer 4

The net movement of particles from an area of high concentration to an area of lower concentration with the use of a membrane protein

Question 5

Explain the process of facilitated diffusion with carrier proteins

Answer 5

1. A large molecule attaches to the carrier protein
2. The protein changes shape
3. This releases the molecule on the other side of the membrane

Question 6

Explain the process of facilitated diffusion with channel proteins

Answer 6

channel proteins form pores in the membrane for charged particles (no change in shape)
Different channel proteins facilitate the diffusion of different charged particles

Question 7

Factors which affect the rate of facilitated diffusion

Answer 7

Concentration gradient - Greater the concentration gradient the faster the rate of diffusion until an equilibrium is reached.
The number of channel and carrier proteins - once all proteins are in use facilitated diffusion can’t happen any faster so the number of proteins increases the rate of diffusion