Movement into and out of Cells

Worked examples (12)extended set

• 1Which way do the gases diffuse?
• 2Which processes need energy from respiration? (multiple choice)
• 3Gas exchange between a capillary and a muscle cell
• 4Why diffusion matters to living organisms
• 5Conditions for the fastest diffusion in fish gills (multiple choice)
• 6Agar cubes: results table from stop-clock readings
• 7Concentration of ammonia and the rate of diffusion
• 8Distance diffused against time
• 9Exchange across the placenta
• 10Why a flatworm needs no gas exchange organ
• 11Planning an investigation into temperature and diffusion
• 12Processing results with an anomaly

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 6 (Alternative to Practical) style

Worked examples (12)extended set

• 1Water as a solvent in digestion, excretion and transport
• 2Visking tubing and a rising capillary tube
• 3Direction of water movement between cells (multiple choice)
• 4Turgid and plasmolysed epidermis cells
• 5Root hair cells in salty soil
• 6Percentage change in mass of potato cylinders
• 7Reading a length-ratio graph (multiple choice)
• 8Dilutions, a results table and a conclusion for carrot strips
• 9Planning an osmosis investigation with sweet potato
• 10Finding where no water moves from a graph
• 11Why jam and salted fish do not go off
• 12Red blood cells in salt solutions

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 6 (Alternative to Practical) style
• ✓Model answer — Paper 4 (Extended) extended-response style

Worked examples (12)extended set

• 1Spotting active transport on a membrane diagram
• 2Which movement is active transport? (multiple choice)
• 3True statements about active transport (multiple choice)
• 4Explaining potassium ion uptake by a root hair cell
• 5Why roots need active transport
• 6Ion concentrations in a pondweed and its pond
• 7Temperature and the rate of ion uptake
• 8Crops in compacted soil
• 9Absorbing the last of the glucose in the small intestine
• 10Living and boiled potato discs: a control experiment
• 11When all the carriers are in use
• 12How active transport helps roots take up water

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) data-response style
• ✓Model answer — Paper 4 (Extended) extended-response style