4.2 diffusion

Question 1

diffusion definition

Answer 1

the movement of molecules or ions from a region where they are more highly concentrated to one where their concentration is lower until evenly distributed

Question 2

what is the difference between simple diffusion and facilitated diffusion? (4)

Answer 2

• simple diffusion-> involves small, non-polar molecules
• facilitated diffusion-> involves charged ions or polar molecules
• simple diffusion-> no carrier proteins or protein channels
• > facilitated diffusion-> carrier proteins or protein channels

Question 3

what are protein channels?

Answer 3

water-filled tubes

Question 4

what do protein channels allow through?

Answer 4

allow water-soluble ions to diffuse across the membrane

Question 5

how do carrier proteins allow substances through?

Answer 5

• bind to ion

- change shape in order to move these molecules across the membrane