Biology 9700 · AS & A Level · Infectious diseases

Infectious diseases — practice question

Diseases can be classed as infectious or non-infectious.
(a)[4]

Complete Table 4.1 so that it gives a summary of four important infectious diseases.

(b(i))[1]

State which disease in Table 4.1 is spread in the same way as typhoid.

(b(ii))[1]

State which type of drug may be used to treat typhoid. Give a reason for your answer.

(b(iii))[2]

Child vaccination programmes against typhoid in some countries have been very successful. The number of people contracting the disease has fallen not only among the vaccinated children, but also in other age groups that were not included in the programme. Suggest explanations for this observation.

(c(i))[3]

After infection, the typhoid bacteria are engulfed by phagocytes. Explain why the phagocytes act on the bacteria only and not on human cells.

(c(ii))[1]

Unlike other bacteria, typhoid bacteria can survive and multiply inside phagocytes. Suggest an explanation for this observation.

(c(iii))[2]

Explain why people with HIV/AIDS are more susceptible to infections such as typhoid.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: Correct disease matched with causative organism (e.g. cholera - bacterium - $\textit{Vibrio cholerae}$)

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