Diffusion

Question 1

What is diffusion?

Answer 1

The passive movement of particles from a high concentration to a low concentration

Question 2

Is simple diffusion passive or active?

Answer 2

Passive

Question 3

Factors that affect rate of diffusion?

Answer 3

Surface area
Thickness of exchange surface
Concentration gradient

Question 4

Is facilitated diffusion active or passive

Answer 4

Passive

Question 5

How do carrier proteins work

Answer 5

Molecule attaches itself to the carrier protein membrane
Then the protein changes shape
Releasing the molecule on the opposite side of the membrane

Question 6

Describe a channel protein and it’s role

Answer 6

Proteins within a membrane that form pores

They allow charged particles to pass through via facilitated diffusion

Question 7

What would happen if you increased the size /width of a membrane

Answer 7

There would be more room for more channel and carrier proteins therefore increasing facilitated diffusion since it would allow more particles to transfer across the membrane at one time

Question 8

How do you calculate the rate of diffusion

Answer 8

Draw a tangent at the curve where it says to e.g 3 seconds
Calculate the gradient
Use right units for diffusion e.g ms^-1