Diffusion

Question 1

What is diffusion?

Answer 1

The net movement of particles from an area of higher concentration to an area of lower concentration

Question 2

Which states of matter can diffusion occur in?

Answer 2

• Gases
• Liquids

Question 3

Diffusion through partially permeable membranes: (E.g: cell membrane)

Answer 3

• Partially permeable - only some molecules can diffuse through them.
• Only small molecules that are dissolved in a fluid inside/outside the cell can diffuse through. E.g: water, glucose & amino acids
• Larger molecules cannot fit through the membrane as they’re too big. E.g: proteins & startch

Question 4

Diffusion is a passive process. What does this mean?

Answer 4

• Doesn’t require any energy from the cell

Question 5

What are the 3 factors that affect the rate of diffusion?

Answer 5

1. • Concentration gradient - The difference in concentration between 2 places.
     - Which ever side contains the most particles, the particles will diffuse from that direction to the other. (e.g: left -> right)
     - The larger the concentration gradient = the higher the rate of diffusion.
2. • Temperature
     - Higher temperatures give the particles more energy, meaning that they will move around faster and diffuse more quickly.
     - Higher temperature = higher rate of diffusion.
3. • Surface area
     - The larger the surface area = higher rate of diffusion