Lesson 3.3.2.2

3.3.2.2 Gas exchange in the human gas exchange system Quiz: AQA Biology, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson 3.3.2.2, Gas exchange in the human gas exchange system: 20 multiple choice questions for the AQA Biology (7402), Unit 3: Organisms exchange substances with their environment, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. What is the main gas exchange surface in the human lung?

    • The alveoli, which are tiny air sacs with a thin epithelium surrounded by capillaries.
    • The bronchi, which are large tubes that carry blood to the heart in large volumes.
    • The trachea, which is a rigid tube containing cartilage that holds open the airway.
    • The bronchioles, which are narrow branches that carry blood away from the lungs.

  2. Which structure in the human gas exchange system carries air from the trachea into the lungs?

    • The spiracles, which open on the body surface to admit air.
    • The bronchi, which divide into smaller bronchioles.
    • The diaphragm, which contracts to pull air into the thorax.
    • The alveoli, which are the site of gas exchange with the blood.

  3. What is the role of the diaphragm in breathing in?

    • It relaxes and rises, increasing the volume of the thorax and raising the pressure inside it.
    • It produces cartilage that holds the bronchi open during inhalation of air.
    • It contracts and flattens, increasing the volume of the thorax and reducing the pressure inside it.
    • It contracts and bulges upwards, reducing the volume of the thorax and forcing air out.

  4. During forced exhalation, which muscles are involved in reducing the volume of the thorax?

    • The external intercostal muscles, which pull the ribs upwards and outwards.
    • The trachea, which contracts to force air out through the bronchioles by peristalsis.
    • The diaphragm, which contracts strongly and flattens to push air out of the lungs.
    • The internal intercostal muscles, which pull the ribs downwards and inwards.

  5. Why is the alveolar epithelium described as an effective surface for gas exchange?

    • It is many cells thick and has a small surface area with no contact with capillaries.
    • It is made of cartilage that holds the airway open and stops gases from passing through.
    • It is covered in a waxy cuticle that prevents any gases from diffusing across it.
    • It is one cell thick and has a very large surface area with close contact to capillaries.

  6. Which description of the antagonistic action of the intercostal muscles during breathing is correct?

    • External and internal intercostal muscles work in opposition to move the ribs up and down.
    • External and internal intercostal muscles both contract together to move the ribs in the same direction.
    • Internal intercostal muscles produce cartilage, while external intercostal muscles produce surfactant.
    • External intercostal muscles act on the trachea, while internal intercostal muscles act on the alveoli.

  7. A patient has damaged alveoli. What is the most likely effect on gas exchange?

    • The surface area for diffusion is reduced, so less oxygen enters the blood and less carbon dioxide is removed.
    • The surface area for diffusion is reduced, but gas exchange is improved by the increased thickness of the epithelium.
    • The surface area for diffusion is unchanged, because gas exchange occurs only in the bronchi.
    • The surface area for diffusion is increased, so more oxygen enters the blood and more carbon dioxide is removed.

  8. A study finds that smokers have a higher incidence of lung disease than non-smokers. Which conclusion is most justified?

    • Smoking is correlated with lung disease, but causation needs further evidence to be established.
    • Lung disease causes smoking, so smokers are more likely to develop lung disease in the future.
    • Smoking has been proven to cause lung disease in every individual who smokes, with no exceptions.
    • Smoking has no relationship to lung disease, because only a small proportion of smokers are affected.

  9. Which statement describes how a restriction on a risk factor may be justified by experimental data?

    • Experiments showing a causal link between a risk factor and disease can support statutory restrictions.
    • Experiments with a single participant are sufficient to establish a causal link for the whole population.
    • Experiments showing no effect of the risk factor can be used to introduce new restrictions.
    • Experiments showing a random association between a risk factor and disease can prove causation.

  10. What is pulmonary ventilation rate (PVR) calculated from?

    • Tidal volume divided by breathing rate.
    • Vital capacity divided by the number of alveoli in the lungs.
    • Tidal volume multiplied by breathing rate.
    • Breathing rate multiplied by the surface area of the alveoli.

  11. A person has a tidal volume of 0.5 dm^3 and a breathing rate of 15 breaths per minute. What is their pulmonary ventilation rate?

    • 30 dm^3 per minute
    • 15.5 dm^3 per minute
    • 7.5 dm^3 per minute
    • 0.03 dm^3 per minute

  12. Which feature of the gross structure of the lungs increases the surface area for gas exchange?

    • Millions of alveoli arranged in clusters at the ends of the bronchioles.
    • A single large air sac at the base of the trachea with a thick muscular wall.
    • A thick layer of smooth muscle around each bronchus that limits airflow.
    • Long cartilage rings that surround the trachea and extend to the diaphragm.

  13. A researcher finds that pollution is correlated with an increased incidence of lung disease. What additional step would best test a causal link?

    • Measuring the height of the population, which will show whether pollution causes disease directly.
    • A controlled study that compares exposure to pollution with a control group and measures the disease outcomes.
    • Recording the pollution levels in one city and assuming the disease rate must also be high.
    • Asking a single doctor whether pollution causes disease, and accepting the answer as evidence.

  14. Which of these events occurs during breathing out at rest?

    • The diaphragm contracts and flattens, and the thorax volume increases, drawing air into the lungs.
    • The external intercostal muscles contract and pull the ribs upwards and outwards.
    • The alveoli expand to increase the volume of the thorax and draw air into the lungs.
    • The diaphragm relaxes and rises, and the thorax volume decreases, forcing air out of the lungs.

  15. A patient with lung disease has reduced gas exchange. Which measurement would most directly show a reduction in gas exchange?

    • A lower rate of oxygen uptake and carbon dioxide removal from the alveoli into the blood.
    • A faster breathing rate with no change in the oxygen content of the blood.
    • A higher number of alveoli that are open and functioning in the lungs.
    • A greater tidal volume that is the same as in a healthy person at rest.

  16. What is the function of the cartilage rings in the trachea and bronchi?

    • They produce mucus that traps dust and pathogens in the lining of the airway.
    • They hold the airway open so that it does not collapse during changes in pressure.
    • They contract rhythmically to push air through the alveoli by peristalsis.
    • They absorb oxygen from the inhaled air and pass it into the capillaries directly.

  17. Why does the lining of the alveoli need to be moist for gas exchange to occur?

    • Water absorbs carbon dioxide and converts it into oxygen, which is then passed into the blood.
    • Water inside the alveoli is the main site of carbon dioxide production, so it must be kept moist.
    • Moisture prevents the diaphragm from moving, which keeps the thoracic volume constant during breathing.
    • Gases must dissolve in the thin film of moisture before they can diffuse across the epithelium.

  18. During inspiration, the pressure in the thorax falls below atmospheric pressure. Why does air then flow into the lungs?

    • Air moves from the higher pressure outside down a pressure gradient into the lower pressure in the lungs.
    • Air is pulled in because the alveoli expand and create a vacuum that draws air through the trachea.
    • Air enters because the bronchi produce a suction force that draws air in from the outside.
    • Air flows in because the diaphragm releases a gas that is lighter than air into the thorax.

  19. A student has a tidal volume of 500 cm^3 and a breathing rate of 12 breaths per minute. What is the pulmonary ventilation rate in dm^3 per minute?

    • 4.2 dm^3 per minute
    • 6 dm^3 per minute
    • 60 dm^3 per minute
    • 0.6 dm^3 per minute

  20. A study reports that reduced lung function is correlated with a risk factor in one population only. Which evaluation is best?

    • The finding proves the risk factor causes lung disease, because the study used a real population.
    • The finding alone cannot establish causation, because other factors in that population may explain the link.
    • The finding shows the risk factor has no effect, because correlation between two factors means there is no link.
    • The finding is invalid, because lung function cannot be measured reliably in any population at all.

All AQA Biology quizzes