Biology 9700 · AS & A Level · Infectious diseases

Infectious diseases — practice question

A group of students was examining the characteristics of several human pathogens. One student drew up a flow chart to sort out four different human pathogens. The student relied on information about the structure and the transmission route of each pathogen. Fig. 3.1 shows the flow chart with some parts still missing.
(a)[5]

Finish the flow chart in Fig. 3.1 by naming the modes of transmission, the scientific names of the pathogens, and one disease caused by each.

(b)[2]

Suggest the mechanism of action of tenofovir to stop reverse transcriptase from synthesising DNA. Use the information in Fig. 3.2 in your answer.

(c(i))[1]

Calculate the percentage of people who received PrEP in 2019 as a percentage of the target set by the UN in 2016. Give your answer to the nearest whole number.

(c(ii))[4]

PrEP does not prevent HIV from being transmitted. State and explain how health authorities can lower HIV transmission.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: “The insect vector is the Anopheles mosquito” …

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