1 The diagram shows the human lungs and associated structures. … … … (a) Complete the diagram by naming the labelled parts. [3] (b) Explain why a human needs lungs. … … … … … [3] [Total: 6]

1(a) clockwise from right hand side: trachea / windpipe ; 1 Allow cartilage bronchiole ; 1 larynx / voice box ; 1 1(b) any three from: gaseous / gas exchange ; oxygen in + carbon dioxide out AW ; oxygen for respiration / carbon dioxide from respiration ; energy from respiration used for movement / relevant activity ; needs a large surface area / moist surface / blood capillaries close to air / thin membrane ; 3

4 Cardiopulmonary resuscitation (CPR) is a first aid procedure. Air is forced into a patient’s lungs by another person. The heart is made to pump blood by repeated compression of the patient’s chest over the heart. A person performing CPR on a patient is shown in the diagrams. repeated compression of chest air forced into lungs (a) (i) State what will be seen to happen to the patient’s chest when air is forced into the lungs. … [1] (ii) Name, in the correct order, the tubes through which air will travel from the patient’s mouth to the alveoli of the lungs. … … … [2] (iii) The air forced into the patient’s lungs has different concentrations of gases compared to the air the patient would normally breathe in. State two differences in the concentrations of gases. … … … [2] (b) Explain how each action of the CPR procedure will benefit the patient: air forced into the patient’s lungs … … … … repeated compression of the patient’s chest. … … … … [4] [Total: 9]

4(a)(i) rises / expands AW ; 1 4(a)(ii) ALL THREE from the list below = 2 marks ;; OR ANY ONE or TWO from the list below = 1 mark ; left box = larynx / trachea middle box = bronchi / bronchus right box = bronchiole(s) 2 left box Ig windpipe 4(a)(iii) air forced into the lungs has ... 1 less oxygen ; 2 more carbon dioxide ; 3 more water vapour ; 2 4(b) 1 oxygen + lungs / alveoli / air sacs ; 2 oxygen + blood / red blood cells / RBC / erythrocytes / haemoglobin ; 3 diffusion ; 4 high to low concentration / down concentration gradient ; 5 blood from + left ventricle ; 6 blood to + organs / tissues / cells ; 7 aerobic respiration ; 8 re-start the heart ; 4

9 (a) Describe how air is breathed in, using the rib cage and diaphragm, so that it reaches the alveoli. … … … … … … … [5] (b) Bronchitis is a condition that can be triggered by breathing in substances that cause the bronchi to become inflamed and produce a large amount of mucus. Suggest how this condition can affect a person and explain how a person may be able to avoid developing the condition. … … … … … … … [5] [Total: 10]

8(a) any five from: photosynthesis ; in leaves / green parts of plants / in mesophyll / chloroplasts / using chlorophyll ; using light energy ; water + soil / irrigation / roots / root hair cells ; carbon dioxide + air / through stomata ; produce glucose / C6H12O6 ; starch ; magnesium + from soil + to make chlorophyll ; 5 8(b) any five from: greater demand for food ; not enough land available for farming ; land being used for e.g. building / biofuels / deforestation ; increase in greenhouse gases ; (leads to) climate change ; droughts / floods / salinisation AW ; lack of nutrients in soils monoculture / overcrowding AW ; 5 9(a) any five from: contraction of diaphragm ; diaphragm flattens / moves down ; bones of rib cage pulled upwards / outwards ; external intercostal muscles contract / internal relax ; pressure decreases / volume increases ; air passes through nose / trachea / windpipe / larynx ; through bronchi / bronchioles ; 5 9(b) any three from (effect on person): bronchi narrowed / blocked by mucus ; need to cough + remove ; pain (from coughing) ; increase in bacteria / microorganisms ; harder for oxygen to reach alveoli / reduced gaseous exchange ; reduced aerobic respiration ; ability to exercise reduced ; feel tired / lethargic ; any two from (avoiding the condition): avoid smoking / avoid breathing in smoke ; avoid particulate air pollution / use of mask ; avoid places with lots of vehicles ; 5

2 The photograph shows the surface of a mammalian organ. B C A (a) (i) Identify this organ … [1] (ii) Name the structures labelled A … [1] (b) In the space below, make a large drawing of this organ as it appears in the photograph. [5] (c) (i) On the photograph, draw a line between B and C. Measure and record this length. … mm [2] (ii) On your drawing, draw a line at the same location as the line B–C. Measure and record the length of this line. … mm [2] (iii) Use your measurements in (c)(i) and (c)(ii) to calculate the magnification of your drawing compared to the photograph. Give your answer to one decimal place. Space for working. magnification × … [2] [Total: 13]

1(a)(i) 1 attempt to construct a two column / row table with ruled lines ; 2 header for seedling column + 1–6 ; 3 header for height column / row + mm ; 4 six measurements recorded ; 5 correct mean height calculated + mm ; 5 1(a)(ii) difficult to identify which part to measure, i.e. where to start and end AW ; seedlings not straight / too small to measure ; ruler doesn’t start at zero, i.e. additional plastic / wood ; 2 Ig parallax 1(a)(iii) observation: colour observed ; conclusion: correct conclusion for observation e.g. blue-black, starch present ; 2 1(b)(i) 1 time on x-axis + both axes fully labelled ; 2 linear scales with 2 values at origin + plots use at least half the grid on each axis ; 3 all 6 points correctly plotted ; 4 plots joined with ruled lines + no extrapolation to origin or beyond 23 days ; 4 1(b)(ii) growth or mean height increases + time / AW ; faster at start / slower at end ; 2 1(b)(iii) (between) 6–10 days ; 1 1(b)(iv) 0.8 ; mm / day ; 2 A mm per day 1(b)(v) any 2 variables: temperature / (sun)light / water or moisture / same type of seed / number of seeds or seedlings ;; explanation: to ensure that time / the variable you are investigating is the only variable that changes AW ; 3 1(c) 1 several (Petri) dishes ; 2 at least 5 seeds / seedlings in each (Petri) dish ; 3 water / solutions of different pHs used AW ; 4 at least 3 × pH numbers between 1–14 used ; 5 (control variables) temperature / (sun)light / same type of seed / volume of water ; 6 same length of time (minimum one day) ; 7 height of seedlings measured ; 8 sample of at least 3 seedlings + from each dish / pH ; 9 means calculated ; 6 2(a)(i) heart ; 1 2(a)(ii) blood vessel ; 1 A artery / vein R capillary Ig names 2(b) 1 clear and clean outline of heart drawn with a sharp pencil + no shading ; 2 heart at least 70 mm wide ; 3 height greater than width + tapering on both sides to curved base ; 4 surface blood vessel A from top right to bottom left of drawing ; 5 left atrium completely delimited + right atrium higher than left ; 5 2(c)(i) line drawn ; 40 ± 1 ; 2 2(c)(ii) horizontal line drawn at greatest width ; correct measurement to nearest mm ± 1 ; 2 2(c)(iii) measurement in (c)(ii) / measurement in (c)(i) ; correct answer rounded to 1dp ; 2

17 What are features of the alveoli? lined by cilia lined with moisture walls are one cell thick A key B = yes C = no D

Answer: D To earn the mark, a student must correctly identify that alveoli are lined with moisture and have walls that are one cell thick, but are not lined by cilia.

Cambridge O Level Biology · 5090

O-Level Biology (5090) Human gas exchange past paper questions

Revise O-Level Biology (5090) — Human gas exchange 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.

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

Human gas exchange in O-Level Biology 5090 exams, 2020–2025

Across 2020–2025, Human gas exchange accounted for 42 questions worth 153 marks in Cambridge O Level Biology (5090) papers.

By year
Year	Questions	Marks
2020	9	34
2021	11	45
2022	7	28
2023	4	18
2024	5	14
2025	6	14

Most-tested subtopics

9.1 Human gas exchange123 marks

Appears in

Paper 1 · 30 qs
Paper 2 · 10 qs
Paper 3 · 2 qs

All most-tested Biology topics

2021 Oct/Nov · Paper 2 · Q1 · 6 marks
Marking scheme
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2021 May/Jun · Paper 2 · Q4 · 9 marks
Marking scheme
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2021 May/Jun · Paper 2 · Q9 · 10 marks
Marking scheme
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2021 May/Jun · Paper 3 · Q2 · 13 marks
Marking scheme
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2021 Oct/Nov · Paper 1 · Q17 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q17
Answer: D
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