B2.1

Question 1

Define Diffusion

Answer 1

Diffusion is the net (overall) movement of particles from a region of high concentration to a region of low concentration.

Question 2

When does diffusion stop?

Answer 2

Diffusion continues until the concentration of particles is the same everywhere. At this point the concentration gradient is zero

Question 3

Where does diffusion occur in the body?

Answer 3

Diffusion is a process by which particles enter and leave the cells, they pass through the cell membrane from a region of high concentration to a region of low concentration.

Question 4

Factors which affect the rate of diffusion?

To increase the rate of diffusion you need to:

Answer 4

Decrease the distance particles need to move
Increase the concentration gradient
Increase the surface area

Question 5

What is osmosis?

Answer 5

Osmosis is a special type of diffusion. It is the diffusion of water molecules form a selectively permeable membrane.

Question 6

What is the concentration of free water molecules known as?

What happens when a solute is dissolved in water?

Answer 6

Water potential
Pure water has the highest possible water potential
The more concentrated the solution becomes the lower the water potential

When a solute is dissolved in water, water molecules cluster around the solute molecules.
This leaves fewer water molecules that are free to diffuse in other areas

Question 7

Define Osmosis

Answer 7

Osmosis is the movement of water molecules from a high water potential to a low water potential