Free Gas exchange questions for AS Level Biology (9700), part of Transport & disease. Each question has the answer and the marking points an examiner would look for.
Generate a full Gas Exchange worksheet →All Transport & disease questionsWhich row describes tissues in the trachea and bronchioles?
| cartilage | ciliated epithelium | smooth muscle | |
|---|---|---|---|
| A | bronchioles only | both | trachea only |
| B | trachea only | bronchioles only | both |
| C | trachea only | both | both |
| D | both | trachea only | bronchioles only |
Answer: C
The alveoli are adapted for gas exchange.
1 Walls are one squamous epithelial cell thick.
2 Cartilage keeps the alveoli open.
3 Elastic fibres recoil to help expel air.
Which statements are correct?
Answer: B
Which statement describes ciliated epithelium?
Answer: A
Which row describes the effects of tobacco smoke?
| tar | carbon monoxide | nicotine | |
|---|---|---|---|
| A | paralyses cilia, carcinogens | binds haemoglobin | increases heart rate and blood pressure |
| B | paralyses cilia, carcinogens | binds haemoglobin | decreases heart rate |
| C | binds haemoglobin | paralyses cilia, carcinogens | increases heart rate and blood pressure |
| D | paralyses cilia, carcinogens | increases heart rate | binds haemoglobin |
Answer: A
The mammalian gas exchange system has several tissues.
Describe the roles of cartilage, smooth muscle and elastic fibres in the airways.
Explain how goblet cells and ciliated epithelium protect the lungs.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | cartilage keeps open; smooth muscle constricts; elastic fibres recoil cartilage keeps trachea and bronchi open B1 smooth muscle contracts to constrict airways B1 elastic fibres stretch and recoil to expel air B1 | 3 |
| (b) | mucus traps; cilia move mucus goblet cells secrete mucus that traps particles/pathogens B1 cilia beat to move mucus up and away from the lungs B1 | 2 |
This question is about the gas exchange system.
Describe the distribution of cartilage, ciliated epithelium, goblet cells and smooth muscle in the trachea, bronchi and bronchioles.
Explain the roles of goblet cells and cilia in protecting the gas exchange surface.
Explain how elastic fibres in the alveolar walls aid ventilation.
Describe the effects of tar and carbon monoxide in tobacco smoke on the body.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | cartilage: C-rings trachea, plates bronchi, none bronchioles; ciliated epithelium and goblet cells in trachea, bronchi, larger bronchioles; smooth muscle in all, most in bronchioles Any 4 of: trachea: C-shaped cartilage rings; bronchi: irregular cartilage plates; bronchioles: no cartilage; ciliated epithelium and goblet cells line trachea and bronchi (fewer in bronchioles); smooth muscle present throughout, relatively more in bronchioles B4 | 4 |
| (b) | goblet cells secrete mucus that traps pathogens; cilia beat, move mucus up to throat goblet cells secrete mucus B1 mucus traps dust and pathogens B1 cilia beat to move mucus up towards the throat where it is swallowed B1 | 3 |
| (c) | stretch on inspiration; recoil to help expel air elastic fibres stretch when alveoli fill B1 they recoil during expiration, helping to push air out B1 | 2 |
| (d) | tar paralyses cilia, mucus builds up, infections; carcinogens cause cancer; CO binds haemoglobin, less O₂ carried tar paralyses / destroys cilia so mucus accumulates B1 increased chest infections / chronic bronchitis B1 tar contains carcinogens (lung cancer) B1 carbon monoxide combines irreversibly with haemoglobin (carboxyhaemoglobin), reducing oxygen transport B1 | 4 |
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Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in