Gas Exchange in Humans

Worked examples (12)extended set

• 1Labelling the breathing system
• 2Limewater test on inspired and expired air
• 3Reading a lung pressure graph (multiple choice)
• 4Explaining breathing in and forced breathing out
• 5The alveolus as a gas exchange surface
• 6Breathing during exercise: rate, depth and carbon dioxide
• 7How the airway lining traps and removes pathogens
• 8Contracting the internal intercostal muscles (multiple choice)
• 9Damaged alveoli: surface area and tiredness
• 10Investigating the effect of exercise on breathing rate
• 11Explaining why expired air differs from inspired air
• 12What the bell jar model shows, and where it fails

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