Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can define osmosis and explain why water, not solute, moves when solutes cannot cross a membrane. (Guide: “Why water moves into and out of cells”)
- I can use hypotonic, isotonic and hypertonic correctly, always saying what is being compared, and state the direction of net water movement. (Guide: “Tonicity: always a comparison”; Practice Q1)
- I can describe what happens to animal and plant cells in each type of solution, and explain why a plant cell becomes turgid instead of bursting. (Guide: Figure 1; Practice Q1)
- I can explain how a contractile vacuole and a central vacuole help cells keep their water balance. (Guide: “Osmoregulation”; Practice Q5)
- I can explain why osmoregulation matters for growth and homeostasis and why it needs energy. (Guide: “Osmoregulation”; Practice Q6)
Calculation and skills
- I can use Ψ = Ψp + Ψs to find a cell’s water potential and predict which way water will move. (Guide: Worked example 1; Practice Q3)
- I can calculate solute potential with Ψs = −iCRT, using the right value of i and temperature in kelvin. (Guide: “Calculating solute potential”; Practice Q2, Q7)
- I can construct a graph of osmosis data with correct axes, units, scales and error bars where appropriate. (Guide: Worked example 2; Practice Q4)
- I can read an isotonic point from a graph and convert it into a water potential. (Guide: Worked example 2; Practice Q4)
Reasoning
- I can explain why a cell placed in a solution reaches equilibrium, using the change in pressure potential. (Guide: Worked example 1; Practice Q7)
- I can explain how an organism keeps its internal solute concentration different from its surroundings, using fish or protists as examples. (Guide: “Osmoregulation”; Practice Q6)
All ticked? Move on to Topic 2.8, Mechanisms of Transport, or return to the course roadmap.