Infectious diseases: past paper questions
Real questions on infectious diseases
The newest 20 of 125 written questions, plus 119 multiple-choice. Open one to see it on the real paper.
- 9700/21 · October/November 2025 · Q4b[4]
V. cholerae is a pathogen that causes cholera. Scientists studied the transmission of V. cholerae in groups of people living in an area where there is a high number of cases of cholera. Some families living in this area filtered their water through several layers of folded fabric from old clothing. The folded fabric tr...
See it on the paper → - 9700/21 · October/November 2025 · Q4c(i)[1]
Describe one change in behaviour that a person can make, other than purifying water, to help prevent a serious case of cholera.
See it on the paper → - 9700/21 · October/November 2025 · Q4c(ii)[2]
The antibiotic tetracycline is used to treat cholera. However, some bacteria that cause cholera have evolved resistance to this antibiotic. Scientists have reported that resistant bacteria have an extra protein in their cell surface membrane. This protein has been found to use ATP. Suggest how the presence of this prot...
See it on the paper → - 9700/21 · October/November 2025 · Q4c(iii)[2]
For some vaccines, there may not be an effective secondary immune response when a person is infected by the specific pathogen. The antibodies that are produced do not act on the pathogen. This is known as immune evasion. Evolution of resistance of bacteria to antibiotics occurs more frequently than immune evasion. Sugg...
See it on the paper → - 9700/22 · October/November 2025 · Q2a[1]
Name the species of bacterium that causes cholera.
See it on the paper → - 9700/22 · October/November 2025 · Q2b[4]
The World Health Organization (WHO) recommends a number of different approaches for the prevention and control of cholera. Two of these are: • • Authorities should provide access to safe drinking water. Individuals and communities should practise preventive personal hygiene. Suggest and explain how these two approaches...
See it on the paper → - 9700/22 · October/November 2025 · Q2c(i)[4]
Complete Table 2.1 to compare an OCV and passive immunisation for cholera: • • fill in the empty box in row 1 circle the correct answers from the choices given in rows 3, 4 and 5. Table 2.1 oral cholera vaccine passive immunisation for cholera row feature 1 component causing the desired response 2 type of immunity gain...
See it on the paper → - 9700/23 · October/November 2025 · Q5a[2]
Suggest why erythromycin can inhibit translation in the bacterium that causes cholera and not inhibit translation in humans who are infected with this pathogen.
See it on the paper → - 9700/23 · October/November 2025 · Q5b[1]
State why penicillin does not act on human cells.
See it on the paper → - 9700/23 · October/November 2025 · Q5c[1]
Explain one way in which rifampicin may inhibit the action of RNA polymerase in transcription.
See it on the paper → - 9700/41 · October/November 2025 · Q2b(i)[2]
Explain how Fig. 2.1 can be used to determine which parent maize variety shows the greatest resistance to infection by E. turcicum.
See it on the paper → - 9700/41 · October/November 2025 · Q2b(ii)[1]
State the name of the type of variation shown by the maize F2 generation in Fig. 2.1.
See it on the paper → - 9700/42 · October/November 2025 · Q4a[2]
Name two ways in which a bacterium can become resistant to an antibiotic.
See it on the paper → - 9700/42 · October/November 2025 · Q4b[1]
Suggest one way in which this contributes to solving the problem of antibiotic resistance in bacteria. (b) The World Health Organisation regularly analyses bacterial DNA sequence data.
See it on the paper → - 9700/42 · October/November 2025 · Q4c[3]
Some infectious bacterial diseases are treated with the antibiotic streptomycin. If a person does not finish the prescribed course of streptomycin, bacteria are more likely to become resistant to the antibiotic. Explain why a streptomycin‑resistant strain of bacteria is more likely to develop as a result of natural sel...
See it on the paper → - 9700/22 · May/June 2025 · Q4a[1]
Although there are two main species of bacterium causing TB, it is rare for the species that causes bovine TB in cattle to infect humans. Name the species of bacterium that is the main cause of TB in humans.
See it on the paper → - 9700/22 · May/June 2025 · Q4b[2]
Explain how the pathogen named in (a) is transmitted from a person with the disease to a person who is uninfected.
See it on the paper → - 9700/22 · May/June 2025 · Q4c[1]
State the type of therapeutic drug used to treat TB.
See it on the paper → - 9700/22 · May/June 2025 · Q4e[5]
In some people with TB, areas known as granulomas may form in lung tissue as part of an immune response to the pathogen. Fig. 4.2 is a photomicrograph of a granuloma in lung tissue. multinucleated giant cells, formed by the fusion of many macrophages staining blood cells outer area of dead cells and infected cells (mai...
See it on the paper → - 9700/43 · May/June 2025 · Q2a(i)[4]
A mutation in a bacterial gene can give resistance to an antibiotic. Directional selection can occur when the antibiotic is present in the environment. A bacterium can also gain resistance when it receives genetic material from another bacterium in a process known as horizontal gene transfer. Outline how directional se...
See it on the paper →
What examiners said
Most responses clearly stated the defining features of an infectious disease.
— Examiner report, February/March 2025, 9700/22 Q4(a)(i) (Cambridge)
Most candidates were able to recall the names of one of the species of bacteria that cause tuberculosis (TB). Not all were able to spell the scientific name correctly.
— Examiner report, February/March 2025, 9700/22 Q4(c)(i) (Cambridge)
Many responses included two or more relevant features, but few provided a complete answer. Most suggested treating TB with a combination of rifampicin and an indigestion drug, with many explaining that this would improve the effectiveness of the treatment by preventing the bacterium from pumping out the antibiotic through the cell surface membrane. Few developed this further by considering that th...
— Examiner report, February/March 2025, 9700/22 Q4(c)(ii) (Cambridge)
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