🧪
Interactive tool -- concept map, worked example & exam question
Compare the three processes, see a worked example then try one yourself, then a real AQA exam question
→
Watch first
▶
MyGCSEScience · AQA Biology
Osmosis — watch on MyGCSEScience
↗
FreeScienceLessons · AQA Biology · Feb 2026Osmosis — definition, direction, concentration gradient
Cognito · AQA Biology · 2026/27 examsOsmosis — water potential and concentration
Key facts
Definition — word for word
- Osmosis is the net movement of water molecules across a partially permeable membrane
- From a dilute solution (high water concentration) to a concentrated solution (low water concentration)
- It is a passive process — no energy required
- The membrane allows water through but not large solute molecules
In plant cells — fill in the table
| Condition | What happens to the cell |
|---|
| Dilute external solution | |
| Concentrated external solution | |
| Turgid cells | |
In animal cells — fill in the table
| Condition | What happens to the cell |
|---|
| Dilute external solution | |
| Concentrated external solution | |
| Blood plasma regulation | |
Exam questions — 4 questions · 8 marks
1 markDefinitionAQA 8461 style
Osmosis is defined as the net movement of water molecules across a partially permeable membrane. In which direction does this movement occur?
A From a concentrated solution to a dilute solution
B From a dilute solution (high water concentration) to a concentrated solution (low water concentration)
C From low solute concentration to high solute concentration
D In both directions equally — no net movement
2 marksPlant cellsAQA Jun 2024 P1 Q4.6
A potato piece is placed in a concentrated salt solution. After 30 minutes it has lost mass. Explain why the potato lost mass. (2 marks)
+20 XP
1 markPartially permeable membraneAQA 8461 style
Why must the membrane be partially permeable for osmosis to occur?
A It allows water molecules through but prevents large solute molecules from passing
B It allows all molecules through equally
C It prevents all molecules from passing through
D It only allows large molecules through
2 marksPotato required practicalAQA Jun 2024 P1 Q4 style
Potato pieces at 1.0 mol/dm³ salt solution lost more mass than pieces at 0.5 mol/dm³. Explain why, using osmosis. (2 marks)
+20 XP
Quick recall flashcards
Module complete! 🎉
Score loading...