Free Diffusion questions for IGCSE Biology (0610), part of Movement into & out of cells. Each question has the answer and the marking points an examiner would look for.
Generate a full Diffusion worksheet →All Movement into & out of cells questionsWhat is diffusion?
Answer: B
Which term is described by this statement?
“The net movement of particles from a region of higher concentration to a region of lower concentration, as a result of their random movement.”
Answer: A
Students cut agar cubes of different sizes containing an indicator and put them in acid. The colour change spreads in from the surface.
Predict which cube changes colour completely first.
Explain your answer using the idea of surface area to volume ratio.
Explain why large organisms need specialised gas exchange surfaces.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | smallest cube the smallest cube B1 | 1 |
| (b) | larger SA:V, shorter distance the smallest cube has the largest surface area to volume ratio B1 acid diffuses a shorter distance to reach the centre B1 | 2 |
| (c) | small SA:V, diffusion too slow they have a small surface area to volume ratio B1 diffusion across the body surface alone would be too slow B1 | 2 |
Students investigate diffusion using beetroot cubes in water at different temperatures.
Predict how temperature affects the rate at which red pigment leaves the cubes.
Explain your prediction.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | faster at higher temperature faster at higher temperature B1 | 1 |
| (b) | more kinetic energy; membranes damaged particles have more kinetic energy and move faster B1 at high temperatures the membranes are damaged/denatured B1 | 2 |
Oxygen moves into cells by diffusion.
Define diffusion.
State two factors that increase the rate of diffusion.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | net movement down concentration gradient by random movement the net movement of particles from a region of higher concentration to a region of lower concentration B1 as a result of their random movement B1 | 2 |
| (b) | temperature; concentration gradient; surface area; shorter distance Any 2 of: higher temperature; steeper concentration gradient; larger surface area; shorter diffusion distance B2 | 2 |
Gases move by diffusion in plants and animals.
Explain why carbon dioxide diffuses into a leaf during the day.
Explain why diffusion is important for single-celled organisms.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | used in photosynthesis, lower inside carbon dioxide is used in photosynthesis B1 so its concentration inside the leaf is lower than outside B1 | 2 |
| (b) | exchange across surface they obtain oxygen and remove waste across their surface by diffusion B1 | 1 |
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