Antimicrobial plants and drug testing: Edexcel International A Level Biology questions

Every Edexcel International A Level Biology exam question on Antimicrobial plants and drug testing (specification points 4.10–4.13), 2019–2025, with its mark scheme and examiner’s report.

All 62 questions on Antimicrobial plants and drug testing, as a list

June 2025, AS Unit 2, Q5(b) (4 marks): Substances derived from plants can have antimicrobial properties. The antimicrobial properties of an extract made from olive oil were investigated. The same num
October 2024, AS Unit 2, Q7(b)(i) (3 marks): Calculate the standard deviation for this set of data. Use the student’s table and formula to help you. (3) Answer mm
October 2024, AS Unit 2, Q7(b)(ii) (1 mark): Which of the following explains why the student would want to calculate the standard deviation(s) (SD) for this experiment? (1) A to see how widely the diameter
October 2024, AS Unit 2, Q7(c)(i) (1 mark): Which percentage of the initial group of patients were placed in group B? (1) A 8.3 % B 8.5 % C 49.5 % D 50.5 %
October 2024, AS Unit 2, Q7(c)(ii) (1 mark): Suggest how this study could be carried out as a double-blind trial. Use the diagram to support your answer. (1)
October 2024, AS Unit 2, Q7(c)(iii) (4 marks): The table shows the mean difference in circumference for the infected and non-infected legs at 5 and 10 days after treatment began. Mean difference in circumfer
October 2024, AS Unit 3, Q3(a)(i) (2 marks): Explain why the dishes were incubated for 48 hours at 30°C. (2) 48 hours 30°C
October 2024, AS Unit 3, Q3(a)(ii) (3 marks): Explain three aseptic techniques that should be used when transferring bacteria from one culture to another. (3) 1 2 3
October 2024, AS Unit 3, Q3(b)(iii) (4 marks): The table shows the results from this investigation. Diameter of zone of inhibition / mm Type of bacteria oil A oil B B. subtilis 20.66 11.33 E. coli 8.66 0.00
October 2024, AS Unit 3, Q3(c)(ii) (2 marks): A method that avoids this problem is to find the minimum inhibitory concentration (MIC) of the extract. The MIC can be defined as the minimum concentration of t
October 2024, Unit 5, Q8(h) (1 mark): Give one reason why a placebo was used in the donanemab trial (Paragraph 33). (1)
June 2024, AS Unit 3, Q3(a)(iv) (3 marks): A coating made from a combination of chitosan and cinnamon oil was also tested. Describe an investigation to determine if this coating is more effective than th
June 2024, AS Unit 3, Q3(b)(iv) (3 marks): The table shows some differences between the method using bacteria and the method using fungi. Type of Incubation Length of Type of agar microorganism temperatu
June 2024, AS Unit 3, Q3(b)(v) (4 marks): The antimicrobial activity was compared by measuring the diameter of the zone of growth inhibition. The greater the diameter, the greater the antimicrobial acti
January 2024, AS Unit 2, Q2(b)(i) (2 marks): Plant‑based packaging is more sustainable than oil‑based packaging. Explain what is meant by sustainable. (2)
January 2024, AS Unit 2, Q2(b)(ii) (4 marks): The effect of packaging material on the growth of viable bacteria on the surface of fish was investigated. The number of S. aureus bacteria on four groups of fi
January 2024, AS Unit 2, Q4(c) (5 marks): The photograph shows part of a Madonna lily plant (L. candidum). (Source: © Zoonar GmbH/Alamy Stock Photo) An extract made from L. candidum has been used in tra
October 2023, AS Unit 2, Q4(c)(i) (2 marks): Explain why an optimum temperature and water are needed for bacterial growth. (2) Optimum temperature Water
October 2023, AS Unit 2, Q4(c)(ii) (3 marks): Explain the results for these two types of bacteria shown in the graph. (3)
October 2023, AS Unit 2, Q6(b)(i) (1 mark): Which of the following describes the purpose of the current pain‑relieving drug in stage II of the drug trial? (1) A control B digitalis C placebo D solvent
October 2023, AS Unit 2, Q6(b)(ii) (4 marks): Describe the processes that would have occurred before and after stage II in this tetrodoxin drug trial. (4)
October 2023, AS Unit 2, Q6(c) (4 marks): The graph shows the duration of pain relief using both tetrodoxin and the current pain‑relieving drug in stage II of this drug trial. Key Tetrodoxin Current pai
June 2023, AS Unit 2, Q3(c)(ii) (2 marks): The fluid of the pitcher plant contains water and molecules from digested organisms, which bacterial cells need for growth. Explain two other conditions needed
June 2023, AS Unit 2, Q7(c)(i) (3 marks): Explain the purpose of the gel used in these treatments. (3)
June 2023, AS Unit 2, Q7(c)(ii) (4 marks): Comment on the results of this investigation. (4)
June 2023, AS Unit 3, Q3(a)(i) (2 marks): Explain two reasons why aseptic techniques were used in this study. (2) 1 2
June 2023, AS Unit 3, Q3(a)(ii) (4 marks): Describe a method to obtain the data in this graph. (4)
June 2023, AS Unit 3, Q3(c)(i) (1 mark): Calculate the ratio of the inhibition for the ethanol extracts of roselle and clove. (1) Answer
June 2023, AS Unit 3, Q3(c)(ii) (2 marks): Describe two conclusions that can be drawn from the results of this investigation. (2) 1 2
June 2023, AS Unit 3, Q3(d) (2 marks): In another study, the effect of these extracts on the internal pH of the cells of E. coli was investigated. The internal pH of E. coli was reduced by each of th
January 2023, AS Unit 2, Q5(b) (6 marks): Bacterial growth and survival can be affected by changing conditions. The effect of temperature and desiccation (water removal) on different bacteria was invest
January 2023, AS Unit 2, Q6(a) (3 marks): The antimicrobial properties of an extract from this plant were investigated. Three sets of agar plates were poured. Each set had a different type of bacteria s
January 2023, AS Unit 2, Q6(b)(i) (4 marks): Evaluate the results of this investigation. (4)
January 2023, AS Unit 2, Q6(b)(ii) (3 marks): Drug A was then used in a three-phase drug trial. Compare and contrast phases II and III in a contemporary drug trial using drug A. (3)
October 2022, AS Unit 2, Q4(a)(i) (3 marks): Bacteria can grow on the surfaces of chopping boards. Explain the conditions that would result in the greatest bacterial growth on the surface of a chopping boa
October 2022, AS Unit 2, Q4(b)(i) (3 marks): Comment on the results of this investigation. (3)
October 2022, AS Unit 2, Q4(b)(ii) (1 mark): Suggest one reason for the difference in bacterial survival on the pine chopping board and on the plastic chopping board. (1)
October 2022, Unit 4, Q6(a) (3 marks): Drug ATD was recently approved for the treatment of Alzheimer’s disease. Describe the information that had to be collected by scientists before this drug could
June 2022, AS Unit 2, Q2(b) (4 marks): The effect of concentrations of sodium chloride solution on the growth of bacteria was investigated. The same number of L. piscium bacteria were added to test t
January 2022, AS Unit 2, Q5(b) (2 marks): The photograph shows a bottle of oil extracted from the plant oregano. This plant is native to Mediterranean and western Asian countries. (Source: © Frank Hecke
January 2022, AS Unit 2, Q5(c)(i) (1 mark): Which type of bacteria was least affected by fucoxanthin? (1) A E. coli B S. aureus C L. monocytogenes D P. aeruginosa
January 2022, AS Unit 2, Q5(c)(ii) (1 mark): The table shows the mean and the range of the diameter of the zone of inhibition for each type of bacteria. Calculate the maximum difference in the diameter of
January 2022, AS Unit 2, Q5(d) (3 marks): Drugs containing these chemicals must be tested for safety before they can be approved and used to treat humans. Three‑phase testing can be used to check for th
January 2022, AS Unit 3, Q1(a)(i) (2 marks): State a suitable dependent variable with units for this investigation. (2) Dependent variable Units
January 2022, AS Unit 3, Q1(a)(ii) (5 marks): Describe a safe method, that uses your dependent variable, to obtain the results shown in the graph. (5)
January 2022, AS Unit 3, Q1(a)(iii) (2 marks): Calculate the percentage difference in the effects of the methanol extract and gentamicin on S. typhimurium. Give your answer to two significant figures. (2) An
January 2022, AS Unit 3, Q1(a)(iv) (4 marks): Comment on the antimicrobial effect of extracts of the Arencho plant. (4)
January 2022, AS Unit 3, Q1(b) (4 marks): In a further study, the chemicals β-sitosterol and stigmasterol were purified from the methanol extract. The antimicrobial properties of these chemicals were me
January 2022, AS Unit 3, Q1(c) (3 marks): Plant extracts can be used to make new drugs for the treatment of infections. In trials to test these drugs, placebos and double-blind trials are used. Explain
October 2021, AS Unit 2, Q4(a) (2 marks): Large quantities of this organism need to be grown in a culture medium in order to extract enough curacin A. The culture is kept at the optimum temperature for
October 2021, AS Unit 2, Q4(b)(i) (1 mark): Which of the following scientists tested the effectiveness of digitalis soup? (1) A Adolf Fick B Matthew Meselson and Franklin Stahl C Godfrey Hardy and Wilhelm
October 2021, AS Unit 2, Q4(b)(ii) (2 marks): Curacin A is being developed as a drug to treat some colon and kidney cancers in humans. Suggest how a suitable dose for cancer treatment would be determined in
October 2021, AS Unit 2, Q4(b)(iii) (4 marks): Describe how a double-blind clinical trial would be performed with this cancer drug. (4)
June 2021, AS Unit 2, Q8(b)(iii) (2 marks): The bacterium Pseudomonas aeruginosa causes lung infections in humans. Describe how a drug containing flavonoids could be tested in a stage II drug trial. (2)
June 2021, AS Unit 3, Q1(a) (5 marks): Describe a method that can be used to study the antimicrobial properties of a plant extract. (5)
June 2021, AS Unit 3, Q1(b)(ii) (4 marks): Evaluate the antimicrobial effects of these extracts. Use the data to support your answer. (4)
January 2021, AS Unit 2, Q1(b)(ii) (3 marks): Decomposition of bioplastic bags occurs faster if there is increased bacterial growth. Explain the conditions needed for increased bacterial growth. (3)
October 2020, AS Unit 2, Q5(c) (2 marks): Anticancer drugs have to undergo double‑blind trials before they are used to treat patients. Describe how a placebo is used in a double‑blind trial. (2)
October 2020, AS Unit 2, Q6(a) (4 marks): Explain the conditions needed for the growth of bacteria. (4)
October 2020, AS Unit 2, Q6(b)(i) (2 marks): Calculate the percentage decrease in the mean areas of ulcer of the rats treated with omeprazole compared with the control rats with ulcer. (2) Answer %
October 2020, AS Unit 2, Q6(b)(ii) (6 marks): Explain the results of this investigation. Use all the information in Question 6 to support your answer. (6)
June 2019, AS Unit 2, Q5(b)(ii) (6 marks): The ironwood tree has wood containing chemical compounds called naphthoquinones. These compounds have antibacterial properties. Scientists are investigating whe

Questions, mark schemes and examiner’s reports are © Pearson Edexcel, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? Every Edexcel International A Level Biology paper.

Rather write your answers by hand on iPad? Plumi marks them against the same mark schemes.

3,127 questions