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Cell BiologyRequired Practical

Required Practical: Investigating Osmosis

Part of Cell Transport · GCSE GCSE Biology revision

This required practical covers Required Practical: Investigating Osmosis within Cell Transport for GCSE Biology. Diffusion, osmosis, active transport, factors affecting transport, surface area to volume ratio, and practical investigations It is section 7 of 19 in this topic. Revise both the method and the reason for each step, because practical questions often test understanding rather than pure recall.

Topic position

Section 7 of 19

Practice

23 questions

Recall

20 flashcards

🧪 Required Practical: Investigating Osmosis

Method - Effect of Salt Concentration on Potato Tissue

  1. Prepare specimens: Cut potato into identical chips (same size and shape)
  2. Initial measurement: Measure and record initial mass of each chip
  3. Set up solutions: Place chips in different salt concentrations:
    • 0% (distilled water)
    • 0.2%, 0.4%, 0.6%, 0.8%, 1.0% salt solutions
  4. Control variables: Same volume of solution, same temperature, same time period
  5. Leave for 24 hours
  6. Final measurement: Remove chips, pat dry carefully, re-weigh
  7. Calculate: Percentage change in mass = (Final mass - Initial mass) ÷ Initial mass × 100

Expected Results and Explanation

Salt Concentration Expected Result Explanation
0% (distilled water) Mass increase Hypotonic - water enters by osmosis
0.2% - 0.4% Small mass increase Still hypotonic but less water movement
~0.5% (isotonic point) No change in mass Same concentration as potato cells
0.6% - 1.0% Mass decrease Hypertonic - water leaves by osmosis

🎯 How to Improve Accuracy

  • Use more potato chips for each concentration (larger sample size)
  • Repeat the experiment multiple times to identify anomalies
  • Control temperature throughout the experiment
  • Use more intermediate concentrations for detailed results
  • Pat chips dry more consistently to remove surface water
  • Use the same variety of potato
  • Measure mass to more decimal places

Keep building this topic

Read this section alongside the surrounding pages in Cell Transport. That gives you the full topic sequence instead of a single isolated revision point.

Real-World Applications of Cell TransportCell Transport Overview DiagramThe Cell's Transport SystemCell Transport — Tap to Explore the 3 Mechanisms

Practice Questions for Cell Transport

Which statement best describes diffusion?

  • A. The movement of particles from a region of low concentration to high concentration
  • B. The net movement of particles from a region of high concentration to low concentration
  • C. The movement of water molecules through a partially permeable membrane
  • D. The movement of particles using energy from respiration
1 markfoundation

Explain how osmosis causes a plant cell to become plasmolysed when placed in a concentrated sugar solution.

3 marksstandard

Quick Recall Flashcards

Define osmosis
The movement of water molecules from an area of high water concentration (low solute concentration) to an area of low water concentration (high solute concentration) through a semi-permeable membrane.
Define diffusion
The movement of particles from an area of high concentration to an area of low concentration down a concentration gradient. No energy is required (passive process).

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Cell Transport Overview Diagram