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

4 (a) Antibiotics are drugs that are used to kill bacteria. A scientist investigates antibiotic resistance in bacteria. The scientist uses four different antibiotics discs A, B, C and D. The results are shown in Fig. 4.1. The white areas show where no bacteria have grown. The dark areas show where bacteria have grown. A B C D no bacterial growth bacterial growth Fig. 4.1 (i) Identify the antibiotic that is most effective against the bacteria. … [1] (ii) Identify the antibiotic that the bacteria are most resistant to. … [1] (b) The development of antibiotic resistance is an example of evolution by natural selection. (i) Complete the sentences to describe how strains of bacteria with antibiotic resistance develop. A mutation occurs which causes a change in the … . This mutation causes some bacteria to be resistant to antibiotics. Antibiotics kill non-resistant bacteria. Resistant bacteria survive and … . The … for resistance is passed on to their offspring. Eventually all the population of bacteria will be resistant to antibiotics. [3] (ii) Describe one way natural selection is different from artificial selection. … … [1] (c) Bacteria reproduce by a type of asexual reproduction. State one advantage and one disadvantage of asexual reproduction. advantage … … disadvantage … … [2] [Total: 8]

4(a)(i) D ; 1 4(a)(ii) C ; 1 4(b)(i) chromosome / gene ; reproduce / AW ; allele ; 3 4(b)(ii) traits / characteristics, are selected by humans (in artificial selection) / traits are selected by the environment in natural selection ; traits / characteristics, are usually chosen for economic reasons (in artificial selection) / traits are beneficial for survival in natural selection ; faster results (from artificial selection) / ORA ; (artificial selection only) takes place in selected individuals / natural selection takes place in whole populations ; (artificial selection) does not lead to evolution / ORA ; (artificial selection) results in decreased (genetic) variation / diversity / ORA ; (artificial selection) leads to increased likelihood of inherited / genetic disease ; AVP ; max1 4(c) advantages: no mates required / rapid / AVP ; disadvantages no (genetic) diversity / no evolution / extinction more likely ; 2

2 A student investigates the heart rate of Daphnia. Daphnia are small animals that live in water. Procedure The student: • measures the heart rate of a Daphnia in water • records in Table 2.1 the number of heartbeats in 1 minute • repeats this measurement two more times • adds some cola, coffee or tea to three separate samples of water containing Daphnia. The student repeats the procedure with each water sample. Table 2.1 solution heart rate / beats per minute trial 1 trial 2 trial 3 average water 194 287 299 260 cola 374 389 378 tea 415 409 402 409 coffee 316 324 313 318 (a) Calculate the average heart rate for Daphnia in cola. Record in Table 2.1 this value to the nearest whole number. [2] (b) On the grid draw a bar chart of average heart rate (vertical axis) against solution. Use the values in Table 2.1. [3] (c) Cola and tea contain a chemical called caffeine. Use your bar chart to describe the effect caffeine has on the average heart rate of Daphnia. … [1] (d) (i) Explain why the average result for heart rate of Daphnia in water is not reliable. … … [1] (ii) Suggest how the student can make this average result for the heart rate of Daphnia in water more reliable. … … [1] (iii) Suggest why water with nothing added is used as one of the solutions. … [1] (e) The maker’s of the coffee claim that it does not contain caffeine. Use the data in Table 2.1 and your bar chart to state if you agree with the makers claim. Explain your answer. statement … explanation … … [1] (f) The student uses a different Daphnia for each solution. Suggest why a different Daphnia must be used. … … [1] [Total: 11]

2(a)(i) 380.333 ; 380 (rounded to whole number) ; 2 2(b) axes correct orientation and labelled with units; sensible linear scale and bars cover at least half the grid; bar heights correct ± ½ small square; 3 2(c) increases heart rate / higher ; 1 2(d)(i) has anomalous result / doesn’t fit the pattern / 1st trial too low ; 1 2(d)(ii) do not include experiment 1 in average / carry out a 4th experiment / repeat the anomaly ; 1 2(d)(iii) control/baseline/normal rate ; 1 2(e) disagree / does contain and heart rate in coffee is raised ; 1 2(f) because earlier solution might, be in the daphnia / affect results / no stress to daphnia ; 1

4 (a) Researchers estimated the percentage of people that smoke tobacco in a country. Fig. 4.1 shows the results. 0 10 20 percentage of smokers age group 15 –19 20 – 24 25 – 29 30 – 34 35 – 39 40 – 44 45 – 49 50 – 54 55 – 59 60 – 64 65 –69 70+ 30 40 50 Key male female Fig. 4.1 (i) Describe two general trends shown by the data in Fig. 4.1. 1 … … 2 … … [2] (ii) Calculate the percentage of females that do not smoke tobacco in the 45–49-year-old age group. … % [1] (b) There is a smaller percentage of the population that smoke tobacco compared to 50 years ago. Suggest a reason for this. … … [1] (c) Table 4.1 shows some of the major components of tobacco smoke and their effects on the body. Complete Table 4.1. Table 4.1 component of tobacco smoke effect on the body carbon monoxide … … is an addictive substance … causes cancer [3] (d) One of the effects of smoking tobacco is that ciliated cells lining the airways begin to die. Explain the effects of this on the gas exchange system. … … … … … … [3] (e) Smoking is one of the risk factors for coronary heart disease. State two other risk factors. 1 … 2 … [2] [Total: 12]

4(a)(i) Between 15–29, the percentage increases ; Between 45–70+, the percentage decreases ; AVP ;; max 2 2 4(a)(ii) 68(%) ; 1 4(b) education / legislation / link with lung cancer proved / ban / AVP ; 1 4(c) component of cigarette smoke effect on the body carbon monoxide toxic / binds to haemoglobin (in place of oxygen) ; nicotine ; is an addictive substance tar ; causes cancer 3 4(d) mucus traps, pathogens / particulates ; cilia unable to remove mucus ; decreases surface area of, gas exchange surface / alveoli ; bacteria multiply ; causing, infection / coughing / irritation ; max 3 3 4(e) any two from: stress ; age ; gender ; diet ; genetic predisposition ; AVP ;; 2

Cambridge IGCSE Co-ordinated Sciences · 0654

IGCSE Co-ordinated Sciences (0654) Drugs past paper questions

Revise IGCSE Co-ordinated Sciences (0654) — 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.

8 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 Co-ordinated Sciences 0654 exams, 2020–2025

Across 2020–2025, Drugs accounted for 13 questions worth 110 marks in Cambridge IGCSE Co-ordinated Sciences (0654) papers.

By year
Year	Questions	Marks
2020	1	12
2021	3	31
2022	3	11
2023	1	12
2024	1	12
2025	4	32

Most-tested subtopics

B14.1 Drugs108 marks

Appears in

Paper 2 · 2 qs
Paper 3 · 2 qs
Paper 4 · 7 qs
Paper 6 · 2 qs

All most-tested Co-ordinated Sciences topics

2021 Oct/Nov · Paper 4 · Q1 · 12 marks
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2021 Oct/Nov · Paper 4 · Q4 · 8 marks
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2021 Oct/Nov · Paper 6 · Q2 · 11 marks
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2020 Oct/Nov · Paper 4 · Q4 · 12 marks
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2018 Oct/Nov · Paper 2 · Q7 · 1 mark
Marking scheme
Mark scheme — 2018 Paper 2 Q7
Answer: D
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