1 Fig. 1.1 is a diagram of the human gas exchange system. A region B Fig. 1.1 (a) (i) Identify using a label line and a label on Fig. 1.1: • a lung • the diaphragm. [2] (ii) State the name of structure A in Fig. 1.1. … [1] (iii) Oxygen molecules pass through structure A on their way to the red blood cells. State the names of three other structures in the gas exchange system that oxygen molecules must pass through on their way to the red blood cells. 1 … 2 … 3 … [3] (iv) State the name of the process that moves oxygen into the red blood cells. … [1] (b) Fig. 1.2 is a magnified image of the exchange surface shown in region B in Fig. 1.1. Fig. 1.2 (i) State the name of the main blood vessel that delivers blood to the lungs. … [1] (ii) The gas exchange surface shown in Fig. 1.2 is permeable to make gas exchange efficient. List two other features of gas exchange surfaces. 1 … 2 … [2] (c) Oxygen concentration is higher in inspired air than in expired air. State one other way the composition of inspired air differs from the composition of expired air. … [1] [Total: 11]

1(a)(i) lung correctly identified with a label and a label line ; diaphragm correctly identified with a label and a label line ; 2 1(a)(ii) trachea ; 1 1(a)(iii) any three from : mouth / nose ; larynx ; bronchus / bronchi ; bronchioles ; alveoli ; capillary wall / AW ; plasma ; 3 1(a)(iv) diffusion ; 1 1(b)(i) pulmonary artery ; 1 1(b)(ii) any two from : large surface area ; thin / one cell thick / AW ; good blood supply / many capillaries ; short diffusion, distance / pathway ; 2 1(c) lower carbon dioxide concentration / less water vapour ; 1 To earn marks, you must correctly identify and label the lung and diaphragm on the diagram using both a label line and a label. You also need to name structure A as the trachea, list three other correct structures oxygen passes through (e.g., nose, larynx, bronchi), state 'diffusion' as the process, and identify the 'pulmonary artery' as the main blood vessel. Finally, you must provide two correct features of the exchange surface, such as large surface area or thin walls.

2 (a) Table 2.1 shows the breathing rate of different organisms. Table 2.1 name of organism breathing rate / average number of breaths per minute buffalo 17 camel 8 cat 20 chicken 18 elephant 12 goat 21 horse 10 human 16 sheep 20 (i) State the name of the organism with the lowest breathing rate. … [1] (ii) State the name of two organisms with the same breathing rate. … and … [1] (iii) State the name of the organism with the most similar breathing rate to humans. … [1] (b) A person goes from resting to exercising. Describe how their breathing changes. … … … … … [2] (c) There is more carbon dioxide in expired air than in inspired air. (i) State two other ways the composition of expired air is different from inspired air. 1 … … 2 … … [2] (ii) State the chemical used to test for the presence of carbon dioxide gas and the positive test result. chemical … positive test result … [2] (d) Fig. 2.1 is a diagram of the human gas exchange system. A B C D Fig. 2.1 Identify the parts labelled A, B, C and D in Fig. 2.1. A … B … C … D … [4] [Total: 13]

2(a)(i) camel ; 1 2(a)(ii) cat and sheep ; 1 2(a)(iii) buffalo ; 1 2(b) depth increases ; rate increases ; 2 2(c)(i) less oxygen ; more water (vapour) ; 2 2(c)(ii) limewater ; turns, cloudy / milky / AW ; 2 2(d) A trachea ; B intercostal muscle ; C diaphragm ; D alveoli ; 4 To earn marks, you must accurately identify the organism with the lowest breathing rate, two organisms with the same breathing rate, and the organism with the most similar breathing rate to humans directly from the provided table. For changes during exercise, you need to state that both the depth and rate of breathing increase.

1 (a) Fish, mammals and birds are all groups of vertebrates. (i) State the names of the two other main groups of vertebrates. … and … [1] (ii) Complete Table 1.1 to compare the features of fish, mammals and birds. Table 1.1 feature fish mammals birds organ involved in gas exchange gills lungs circulatory system double body covering fur presence of external ears (pinnae) no [3] (b) Fig. 1.1 is a micrograph of part of some fish gills. magnification ×110 Fig. 1.1 Fish gills are adapted for gas exchange by diffusion. (i) Define the term diffusion. … … … … … [2] (ii) Suggest one adaptation, visible in Fig. 1.1, that shows that fish gills are efficient structures for gas exchange by diffusion. … … … [1] (c) Some pollutants decrease the concentration of dissolved oxygen in rivers. This can result in the death of fish. (i) State one type of pollutant that can result in a decrease in the concentration of dissolved oxygen in rivers. … [1] (ii) Researchers investigated the effect of the concentration of dissolved oxygen in water on gas diffusion distance in tissues. The thickness of fish gills was used to determine the gas diffusion distance. The researchers changed the concentration of dissolved oxygen by bubbling different concentrations of oxygen into water. The temperature of the water was kept constant at 15 °C. Their results are shown in Fig. 1.2. 0.0 7 8 9 10 11 12 6 0.5 1.0 1.5 2.0 2.5 3.0 3.5 dissolved oxygen concentration / mg per dm3 gas diffusion distance / μm Fig. 1.2 Fig. 1.3 shows the relationship between the concentration of dissolved oxygen and water temperature. 6 5 10 15 20 25 30 35 0 7 8 9 10 11 temperature / °C dissolved oxygen concentration / mg per dm3 12 Fig. 1.3 Complete steps 1 to 3 to determine the effect on gas diffusion distance of increasing the temperature of the water from 15 °C to 25 °C. Step 1 Find the concentration of dissolved oxygen from Fig. 1.3 at: 15 °C: … mg per dm3 25 °C: … mg per dm3 Step 2 Use the values from step 1 to find the gas diffusion distances from Fig. 1.2: … µm … µm Step 3 Calculate the difference in the values from step 2. … µm [3] [Total: 11]

1(a)(i) reptiles and amphibians ; 1 1(a)(ii) one mark per row: feature fish mammals birds organ involved in gas exchange gills lungs lungs ; circulatory system single double double ; body covering scales fur feathers ; presence of external ears (pinnae) no yes no ; 3 1(b)(i) (net) movement of particles, from a region of their higher concentration to a region of their lower concentration / down a concentration gradient ; as a result of their random movement ; 2 1(b)(ii) any one from: large surface (area) / AW ; thin ; 1 1(c)(i) nitrate (ions) / sewage / fertilisers / AVP ; 1 1(c)(ii) 15 °C – 8.9 ± 0.1 (mg per dm3) and 25 °C – 7.3 ± 0.1 (mg per dm3) ; 2.35 ± 0.05 (μm) and 1.95 ± 0.05 (μm) ; (–)0.4 (in μm) ; 3 ecf from readings in MP1 for MP2 and MP3 (a)(i) To earn this mark, you need to state the names of the two other main groups of vertebrates, which are reptiles and amphibians. (a)(ii) To earn these marks, you must correctly complete each row of the table: state 'lungs' for birds' gas exchange organ, 'single' for fish's circulatory system, 'feathers' for birds' body covering, and 'yes' for mammals' external ears. (b)(i) To earn these marks, you must define diffusion as the net movement of particles from a region of higher concentration to lower concentration, and mention that this occurs due to their random movement. (b)(ii) To earn this mark, you need to suggest one visible adaptation from the image, such as a large surface area or thinness, that makes fish gills efficient for gas exchange.

5 (a) Table 5.1 shows four functions of the human gas exchange system. Complete Table 5.1 by identifying the part of the human gas exchange system that carries out each function. Table 5.1 function part of the human gas exchange system contracts to decrease air pressure in the lungs allows air to flow between the larynx and the lungs contracts to lower the ribs in forced expiration site of gas exchange [4] (b) Scientists investigated the effect of increasing carbon dioxide concentration in the air on the rate and depth of breathing. The people who took part in the investigation were healthy volunteers. The people breathed atmospheric air containing 0.04% carbon dioxide for five minutes. They then breathed air containing 2% carbon dioxide for five minutes and then returned to breathing atmospheric air for a further five minutes. The results are shown in Fig. 5.1. –20 –10 0 10 16 14 12 10 8 6 4 2 0 20 30 40 50 60 70 depth of breathing rate of breathing key: 0.04% CO2 2% CO2 0.04% CO2 time / minutes percentage change in rate and depth of breathing Fig. 5.1 Describe the effects of changing the carbon dioxide concentration of the air on the rate and depth of breathing, as shown in Fig. 5.1. … … … … … … … … … [4] (c) Complete the sentences by writing the appropriate word or phrase in the spaces provided. During physical activity the carbon dioxide concentration in the blood increases. The reason for this is an increase in the rate of … that occurs in the … in muscle cells. The increase in the concentration of carbon dioxide in the blood is detected by the … , which increases the rate and depth of breathing so that carbon dioxide can be … from the body. This is important because carbon dioxide is a … substance and can cause harm if it accumulates. [5] [Total: 13]

4(b)(ii) any three from: 1 collect semen / sperm (implied by context) ; 2 freeze semen / sperm, / use sperm bank / use sperm collected, far away/ long ago ; 3 selecting / washing / screening, of sperm / AW ; 4 use hormones for (super)ovulation ; 5 determine when female is about to ovulate ; 6 insert, semen / sperm, into female (vagina / uterus) ; 3 5(a) diaphragm / external intercostal muscles ; trachea / bronchus ; internal intercostal muscles ; alveolus / alveoli ; 4 5(b) any four from: 1 (rate and depth of breathing) increase when carbon dioxide concentration increases ; 2 depth of breathing levels off at 9–10 minutes while rate of breathing still going up ; 3 larger increase in rate of breathing than the depth of breathing ; 4 both rate and depth of breathing decrease when the carbon dioxide concentration decreases ; 5 rate and depth of breathing decrease below zero (percentage change) ; 6 rate of breathing does not / depth of breathing starts to, return to zero (percentage change); 7 use of comparative figures for rate of breathing ; 8 use of comparative figures for depth of breathing ; 4 5(c) respiration ; mitochondria ; brain ; excreted / AW ; toxic / poisonous / waste / acid(ic) ; 5

5 The diagram shows some cells. cilia cytoplasm nucleus Where are these cells found? A alimentary canal B blood C bronchus D plant roots

Answer: C To earn this mark, a student must correctly identify the bronchus as the location where these ciliated cells are found.

Cambridge IGCSE Biology · 0610

IGCSE Biology (0610) Gas exchange in humans past paper questions

Gas-exchange questions cover the lungs, breathing, and the effect of exercise.

131 free questions from 2017–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Gas exchange in humans in IGCSE Biology 0610 exams, 2020–2025

Across 2020–2025, Gas exchange in humans accounted for 147 questions worth 543 marks in Cambridge IGCSE Biology (0610) papers.

By year
Year	Questions	Marks
2020	22	80
2021	26	78
2022	28	112
2023	27	98
2024	21	69
2025	23	106

Most-tested subtopics

11.1 Gas exchange in humans433 marks

Appears in

Paper 1 · 53 qs
Paper 2 · 57 qs
Paper 3 · 18 qs
Paper 4 · 17 qs
Paper 5 · 1 q
Paper 6 · 1 q

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2021 May/Jun · Paper 3 · Q1 · 11 marks
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2021 Oct/Nov · Paper 3 · Q2 · 13 marks
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2021 Oct/Nov · Paper 4 · Q1 · 11 marks
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2021 May/Jun · Paper 4 · Q5 · 13 marks
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2021 Oct/Nov · Paper 1 · Q5 · 1 mark
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Mark scheme — 2021 Paper 1 Q5
Answer: C
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