4 (a) Fig. 4.1 is a diagram of the gas exchange system in a human. P Fig. 4.1 (i) Identify the part labelled P in Fig. 4.1. … [1] (ii) On Fig. 4.1, draw a label line and the letter L to identify the larynx. [1] (b) Expired air contains a different percentage of carbon dioxide to inspired air. State and explain this difference. difference … … explanation … … [2] (c) Fig. 4.2 shows cells that line the airways of a non-smoker and a smoker. non-smoker smoker mucus ciliated cell cilia goblet cell Fig. 4.2 Explain how smoking tobacco affects the function of the cells shown in Fig. 4.2. Use the information in Fig. 4.2 in your answer. … … … … … … [3] [Total: 7]

4(a)(i) diaphragm ; 1 4(a)(ii) larynx labelled ; 1 4(b) difference: more carbon dioxide in expired air ; explanation: because produced in respiration ; 2 4(c) any three from: cilia are, damaged / shorter ; (goblet cells make) more mucus ; pathogens / particles, trapped in the mucus ; idea that it is harder (for cilia) to move the mucus ; idea that, pathogens / particles, are not removed (easily) from the airways ; 3

1 (a) A student investigates the volumes of air breathed in and out of their lungs before and during exercise. Fig. 1.1 shows graphs of the results. volume of air / dm3 time / s 2.0 1.5 1.0 0.5 0.0 0 6 12 volume of air / dm3 time / s before exercise during exercise 2.0 1.5 1.0 0.5 0.0 0 6 12 Fig. 1.1 (i) Use data from Fig. 1.1 to calculate the extra volume breathed in with each breath during exercise. extra volume = … dm3 [1] (ii) Use data from Fig. 1.1 to calculate the increase in breathing rate during exercise. Write your answer in breaths per minute. increase = … breaths per minute [2] (b) The pattern of breathing changes during exercise due to the change in the carbon dioxide concentration in the blood. Explain the change in carbon dioxide concentration in the blood. change in concentration … explanation … … [2] (c) Smoking tobacco has harmful effects on the gas exchange system. Describe the effect of carbon monoxide in tobacco smoke. … … … [2] (d) Suggest one disease caused by the tar in tobacco smoke. … [1] [Total: 8]

1(a)(i) (1.5 – 0.6 =) 0.9 (dm3) ; 1 1(a)(ii) (increase in breaths) = 2 breaths (over 12 seconds) ; × 60 / 12 = 10 ; 2 1(b) increase ; (aerobic) respiration increases during exercise ; 2 1(c) combines with haemoglobin / reduces the amount of oxygen able to combine with haemoglobin ; reduces amount of oxygen being transported (by blood / red cells) ; 2 1(d) lung cancer / COPD / emphysema / bronchitis ; 1

1 Fig. 1.1 shows a diagram of the female reproductive system and some events that take place before and during early pregnancy. The fetus is the name for the developing baby. placenta fetus event 1 event 2 event 3 C Fig. 1.1 (a) (i) State what happens during events 1 and 2. event 1 … event 2 … [2] (ii) Name structure C in Fig. 1.1 and state its function. name of C … function of C … … [2] (b) Exchange of substances between blood in the fetus and the mother’s blood takes place at the placenta. Some materials that are transferred across the placenta are shown. amino acids carbon dioxide fatty acids glucose oxygen (i) Name one substance from the list that shows net movement from the fetus into the mother’s blood. …[1] (ii) State the source of this substance in the fetus. … …[1] (iii) Describe how the blood in the fetus reaches the placenta. …[1] (c) Nicotine and carbon monoxide are taken into the blood when a person smokes. Carbon monoxide combines with haemoglobin. This prevents oxygen from being carried in the red blood cells. Suggest why carbon monoxide in the mother’s blood is harmful to the fetus. … … …[2]

1(a)(i) 1 ovulation ; 2 fertilisation ; 2 1(a)(ii) amnion / amniotic membrane ; contains (amniotic) fluid ; 2 1(b)(i) carbon dioxide ; 1 1(b)(ii) (waste product of / produced by) respiration ; 1 1(b)(iii) through umbilical cord ; 1 1(c) reduces oxygen available (to fetus) ; any consequence e.g. reduced respiration / growth ; 2

1 (a) Fig. 1.1 shows a diagram of an alveolus. wall of capillary plasma red blood cell alveolus oxygen Fig. 1.1 (i) On Fig. 1.1 draw an arrow to show the direction of movement of carbon dioxide at the alveolus during gas exchange. [1] (ii) Explain why oxygen molecules diffuse from the alveolus into the blood. … …[1] (iii) Describe two ways in which the structure of the alveolus in Fig. 1.1 makes it suitable for gas exchange. 1. … … 2. … … [2] (b) Describe how a growing baby in the uterus of a pregnant woman obtains glucose. … … …[2] (c) Fig. 1.2 shows apparatus which is used to study the contents of cigarette smoke. A pump draws air through the apparatus. When the cigarette is lit, the smoke produced travels through the apparatus. cigarette cotton wool limewater pump Fig. 1.2 (i) The limewater turns milky. Explain why this happens. … …[1] (ii) Tar from the cigarette is left on the cotton wool. Describe one effect of tar on the gas exchange system. … …[1] (iii) Cigarette smoke damages the cilia that line the airway. Explain why this is harmful. … … …[2] (iv) The lit cigarette also produces carbon monoxide gas. Explain why this is a harmful gas when inspired. … … …[2]

1(a)(i) arrow drawn from the plasma of the blood to the air sac of alveolus ; 1 1(a)(ii) there is a concentration / diffusion gradient / greater oxygen concentration in alveolus than the blood ; 1 1(a)(iii) thin wall / flattened cells ; large surface area ; good blood supply ; Max 2 2 1(b) through placenta ; and then one of by diffusion ; via (umbilical) cord ; Max 2 2 1(c)(i) carbon dioxide / CO2 / produced / present (in smoke) ; 1 1(c)(ii) causes cancer ; stimulates mucus production ; Max 1 1 1(c)(iii) mucus cannot be swept out of the lungs ; pathogens / particles (in mucus) more likely to enter lungs ; 2 1(c)(iv) combines with the haemoglobin / red blood cells ; CO replaces oxygen (on haemoglobin) ; reduces the transport of oxygen by blood / less oxygen available ( for cells) ; Max 2 2

Cambridge IGCSE Combined Science · 0653

IGCSE Combined Science (0653) Drugs past paper questions

Revise IGCSE Combined Science (0653) — Drugs 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.

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

Drugs in IGCSE Combined Science 0653 exams, 2020–2025

Across 2020–2025, Drugs accounted for 12 questions worth 63 marks in Cambridge IGCSE Combined Science (0653) papers.

By year
Year	Questions	Marks
2020	1	1
2021	1	7
2022	4	22
2023	2	8
2024	2	17
2025	2	8

Most-tested subtopics

B13.1 Drugs59 marks

Appears in

Paper 2 · 4 qs
Paper 4 · 8 qs

All most-tested Combined Science topics

2021 Oct/Nov · Paper 4 · Q4 · 7 marks
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2019 Oct/Nov · Paper 4 · Q1 · 8 marks
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2018 Feb/Mar · Paper 4 · Q1 · 9 marks
Marking scheme
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2018 Oct/Nov · Paper 4 · Q1 · 12 marks
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2020 May/Jun · Paper 2 · Q7 · 1 mark
Marking scheme
Mark scheme — 2020 Paper 2 Q7
Answer: A
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