4.2 Diffusion

Question 1

What is diffusion?

Answer 1

Movement of molecules from an area of higher concentration to an area of lower concentration.

Question 2

How can diffusion occur?

Answer 2

When there are different concentrations of the same substance.

Question 3

What is facilitated diffusion?

Answer 3

Diffusion that involves the presence of carrier protein molecules to allow passive movement of substance across membrane.

Question 4

What are channel proteins?

Answer 4

Proteins that form water-filled hydrophilic channels across the membrane.

Question 5

What is the function of channel protein?

Answer 5

Allow specific water-soluble ions to pass through.

Question 6

What are carrier proteins?

Answer 6

Proteins that bind to ions or molecules like glucose and amino acids, then change shape in order to move these molecules across the membrane.

Question 7

What are the factors that affect the rate of diffusion?

Answer 7

1. temperature
2. surface area
3. diffusion distance
4. diffusing molecules
5. concentration gradient
6. water potential
7. number of channel protein
8. number of carrier protein