1 (a) Fig. 1.1 is a diagram of the human gas exchange system. A B Fig. 1.1 (i) Identify the parts labelled A and B in Fig. 1.1. A … B … [2] (ii) List three structures inspired air passes through on its way to the alveoli. 1 … 2 … 3 … [3] (iii) Place a tick (3) in the box to show the blood vessel that brings blood to the lungs. aorta pulmonary artery pulmonary vein vena cava [1] (b) Expired air contains a higher percentage of carbon dioxide than inspired air. (i) State one other way that the composition of expired air is different from inspired air. … … [1] (ii) State the test for carbon dioxide gas and give the observation for a positive result. test … observation … [2] (c) A student records their breathing rate while walking and while running. The results are shown in Fig. 1.2. 0 5 10 15 breathing rate / breaths per minute walking running activity 20 25 30 35 Fig. 1.2 (i) State the breathing rate of the student while walking. … breaths per minute [1] (ii) The student repeats the investigation and records the breathing rate while at rest. Describe the expected changes to the pattern of breathing while at rest when compared to running. … … … [2] [Total: 12]

1(a)(i) A rib ; B diaphragm ; 2 1(a)(ii) any three from nose / mouth ; larynx ; trachea ; bronchus ; bronchioles ; 3 1(a)(iii) pulmonary artery ; 1 1(b)(i) less oxygen / more water (vapour) ; 1 1(b)(ii) substance limewater ; positive result cloudy ; 2 1(c)(i) 20 (breaths / minute) ; 1 1(c)(ii) decrease in breathing rate ; decrease in depth of breathing ; 2

1 (a) Fig. 1.1 is a diagram of the gas exchange system in humans. A B C alveoli Fig. 1.1 (i) Identify the parts labelled A, B and C in Fig. 1.1. A … B … C … [3] (ii) The alveoli are the gas exchange surface in humans. State two features of alveoli that make them efficient gas exchange surfaces. 1 … 2 … [2] (b) Two similar sized groups of people are monitored. One group smoke tobacco (smokers) and the other group do not (non-smokers). The number of smokers and non-smokers of different ages with chronic obstructive pulmonary disease (COPD) are recorded. Fig. 1.2 shows the results. 2500 2000 1500 1000 500 0 number of people with COPD under 45 45–54 age group smokers non-smokers 55–64 65–74 Key Fig. 1.2 Describe the results shown in Fig. 1.2. … … … … … … [3] (c) The tar in tobacco smoke stops the ciliated cells in the gas exchange system from working efficiently. (i) Explain how this would increase the likelihood of infection in the lungs. Include ideas about goblet cells in your answer. … … … … … … [3] (ii) Name the substance in tobacco smoke that is addictive. … [1] [Total: 12]

1(a)(i) A trachea ; B intercostal muscle ; C diaphragm ; 3 1(a)(ii) any two from: good blood supply ; thin ; large surface area ; ventilated ; AVP ; 2 1(b) any two from: COPD increases with age ; more smokers have COPD than non-smokers ; more rapid increase of COPD with age in smokers ; comparative data quote ; 3 1(c)(i) goblet cells produce mucus ; and any two from: mucus traps, pathogens / particles / bacteria ; cilia unable to remove, mucus / pathogens / bacteria ; bacteria, reproduce / multiply (causing infection) ; 3 1(c)(ii) nicotine ; 1

10 (a) The percentage of oxygen in inspired air, in expired air when resting and in expired air during exercise is different. Table 10.1 shows these differences. Table 10.1 percentage of oxygen in inspired air in expired air when resting in expired air during exercise 20 16 14 The percentage of oxygen in expired air when resting and expired air during exercise is different. (i) Calculate the difference. …% [1] (ii) Explain this difference. … … … … [2] (b) Exercise increases the rate of breathing. Describe one other effect of exercise on the pattern of breathing. … … [1] (c) An increase in the concentration levels of one gas in the blood causes the increase in breathing rate. Name this gas. … [1] (d) Alveoli is the gas exchange surface in humans. Name two structures that air must pass through before it reaches the alveoli during inspiration. 1 … 2 … [2] [Total: 7]

10(a)(i) 2(%) ; 1 10(a)(ii) (more) oxygen used in respiration ; to release energy (for exercise) ; 2 10(b) increased depth of breathing ; 1 10(c) carbon dioxide ; 1 10(d) mouth / nose ; larynx ; trachea ; bronchus ; bronchioles ; max 2 2

4 (a) A scientist investigates the recovery time of an athlete and a non‑athlete after exercise. Recovery time is the time taken for the pulse rate to return to normal after exercise. The results are shown in Fig. 4.1. 60 0 0 2 4 6 8 10 12 14 16 time / minutes 18 20 22 24 70 80 pulse rate / beats per minute (bpm) 90 100 110 120 130 at rest during exercise after exercise recovery time recovery time athlete non- athlete Fig. 4.1 (i) State the pulse rate of the non‑athlete at rest. �� bpm [1] (ii) State the length of recovery time for the athlete and the non‑athlete. athlete �� minutes non‑athlete �� minutes [1] (iii) Calculate the difference in recovery times between the athlete and the non‑athlete using your answers to (a)(ii). �� minutes [1] (iv) Describe the changes to the pattern of breathing of the non‑athlete between 4 and 8 minutes. �� [2] (b) During exercise there is increased blood flow through the blood vessels. Fig. 4.2 is a photomicrograph of a cross‑section through an artery. Fig. 4.2 (i) State one piece of evidence from Fig. 4.2 that shows this blood vessel is an artery. �� [1] (ii) Name one component of blood visible in Fig. 4.2. �� [1] (c) The heart is responsible for pumping blood around the body. (i) Name the structure that separates the right and the left sides of the heart. �� [1] (ii) Name the type of tissue the walls of the heart are made from. �� [1] [Total: 9]

4(a)(i) 72 (bpm) 1 4(a)(ii) athlete 3 (minutes) and non-athlete 7 (minutes) ; 1 4(a)(iii) 7 – 3 = 4 (minutes) ; 1 4(a)(iv) breathing rate would increase ; breathing depth would increase ; 2 4(b)(i) thick wall ; 1 4(b)(ii) red blood cell ; 1 4(c)(i) septum ; 1 4(c)(ii) muscular (tissue) ; 1

Cambridge IGCSE Co-ordinated Sciences · 0654

IGCSE Co-ordinated Sciences (0654) Gas exchange in humans past paper questions

Revise IGCSE Co-ordinated Sciences (0654) — Gas exchange in humans with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

54 free questions from 2016–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Gas exchange in humans in IGCSE Co-ordinated Sciences 0654 exams, 2020–2025

Across 2020–2025, Gas exchange in humans accounted for 80 questions worth 353 marks in Cambridge IGCSE Co-ordinated Sciences (0654) papers.

By year
Year	Questions	Marks
2020	13	68
2021	16	44
2022	13	85
2023	7	38
2024	15	43
2025	16	75

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B11.1 Gas exchange in humans302 marks

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Paper 1 · 29 qs
Paper 2 · 22 qs
Paper 3 · 10 qs
Paper 4 · 17 qs
Paper 5 · 1 q
Paper 6 · 1 q

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2021 May/Jun · Paper 3 · Q1 · 12 marks
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2021 Oct/Nov · Paper 4 · Q1 · 12 marks
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2021 May/Jun · Paper 4 · Q10 · 7 marks
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2020 Oct/Nov · Paper 3 · Q4 · 9 marks
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2021 May/Jun · Paper 1 · Q2 · 1 mark
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Mark scheme — 2021 Paper 1 Q2
Answer: C
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