T1.1.4 Diffusion in and between cells Quiz: KS3 Biology, Unit 1

The 20 questions

1. What is diffusion?

   • The movement of water through a membrane only, from the outside to the inside
   • The breakdown of food into smaller molecules by enzymes in the stomach
   • The net movement of particles from a higher concentration to a lower concentration
   • The movement of particles from low to high concentration using energy from the cell

2. Does diffusion need energy from the cell to take place?

   • Yes, it needs energy from the mitochondria to move particles across the cell
   • Only when the particles are dissolved in a liquid and not in a gas
   • No, it is a passive process driven by the movement of particles
   • Yes, it needs a pump in the membrane that moves particles across the cell

3. Oxygen moves into a cell by diffusion because

   • the cell wall pushes it in
   • its concentration is higher outside the cell than inside
   • its concentration is higher inside the cell than outside
   • the cell actively pumps it in

4. Carbon dioxide leaves a respiring cell by diffusion. Where is its concentration highest?

   • In the cell membrane
   • Only in the nucleus
   • In the surrounding air
   • Inside the cell

5. Which example of diffusion happens in the body?

   • Oxygen moving from the lungs into the blood
   • Food being swallowed down the oesophagus
   • Starch being broken into glucose by amylase
   • Water being pumped by the heart

6. Why does the smell of perfume spread across a room?

   • Perfume particles diffuse from high to low concentration in the air
   • The air pushes the perfume out of the bottle and along the room in a current
   • Heat makes the perfume particles grow larger so they drift across the room
   • Perfume particles are attracted to the nose by magnets placed in the room

7. Which change would make diffusion faster?

   • Increasing the temperature
   • Reducing the surface area available
   • Increasing the distance the particles travel
   • Decreasing the temperature

8. Which factor increases the rate of diffusion across a cell boundary?

   • A smaller concentration difference
   • A longer diffusion distance
   • A thicker membrane
   • A larger surface area

9. Diffusion occurs fastest in which state of matter?

   • Liquids
   • Equally fast in all three
   • Gases
   • Solids

10. Diffusion across a membrane stops when

    • all particles have left the cell and no particles remain in the cell at all
    • the concentrations on each side become equal
    • the cell membrane becomes impermeable and blocks all particles from passing
    • the particles stop moving completely and settle on the bottom of the cell

11. Villi in the small intestine have many microscopic projections. Why does this help with diffusion?

    • It pumps digested food across the membrane using energy from the cell
    • It stops digested food from diffusing into the blood by thickening the wall
    • It reduces the surface area of the gut wall to slow diffusion of food into the blood
    • It increases the surface area for digested food to diffuse into the blood

12. Which direction does oxygen diffuse in a leaf?

    • From the stomata into the roots, where it is stored for later use
    • From the leaf into the air through the roots of the plant in the soil
    • From the roots into the air through the stem of the plant in the soil
    • From the air into the leaf through the stomata

13. A cell in the stomach releases carbon dioxide into the blood. Which direction does the gas move?

    • From the blood into the cell, where its concentration is higher
    • From the cell into the blood, where its concentration is lower
    • It stays inside the cell
    • From the blood into the cell, where its concentration is lower

14. A student dissolves sugar in water without stirring. Why does the sugar eventually spread evenly?

    • Water pushes the sugar into all parts of the solution evenly by pressure
    • Diffusion moves particles from high to low concentration until they are evenly spread
    • Sugar particles stop moving once they have dissolved into the water solution
    • Sugar particles are attracted to the cell membrane of the water molecules

15. Which statement about temperature and diffusion is correct?

    • Warmer particles stop moving, so diffusion slows
    • Cooler particles move faster, so diffusion is quicker
    • Warmer particles move faster, so diffusion is quicker
    • Temperature has no effect on particle movement

16. Which substance enters or leaves a cell by simple diffusion?

    • Carbon dioxide
    • Starch granules
    • Solid bile salts
    • Cellulose fibres

17. Which statement explains why a steep concentration gradient matters for diffusion?

    • A steeper gradient means particles move across faster
    • A flat gradient means particles move faster across the membrane than before
    • A steeper gradient means particles stop moving and settle at the bottom
    • Gradients only matter for particles in solids and never in liquids or gases

18. Leaves take in a gas from the air for photosynthesis by diffusion. Which gas is it?

    • Oxygen, which is needed by the leaf cells to release energy in respiration
    • Starch, which is stored in the leaf cells as a food reserve
    • Carbon dioxide
    • Water vapour, which leaves the leaf through the stomata in the day

19. Why is diffusion described as a passive process?

    • It needs ATP from the mitochondria to move particles across the membrane
    • It needs the cell to pump particles against the gradient using energy from food
    • It only occurs in living cells and never in dead or inanimate material
    • It needs no energy from the cell because particles move on their own

20. Which change to a cell membrane would slow the diffusion of particles across it?

    • Making it more permeable, so more particles can pass through
    • Making it thicker, so particles have further to travel
    • Making it thinner, so particles have a shorter distance to cross
    • Making it larger in area, so more particles can reach it

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