(a)[3]
Outline how penicillin acts on bacterial cells.
(b)[1]
Name one of the four species of $\textit{Plasmodium}$ that can cause malaria.
(c)[1]
The male $\textit{Anopheles}$ mosquito does not feed on blood and so does not act as a vector. Suggest why there is a difference in this feeding behaviour between male and female $\textit{Anopheles}$.
(d)[3]
Suggest explanations for the results shown in Fig. 5.1 and comment on the importance of these results for doctors working in countries that have malaria and a high number of bacterial infections.
(e)[4]
Explain the difficulties faced by researchers in developing a malaria vaccine.