Biology 9700 · AS & A Level · Antibiotics

Antibiotics — practice question

In March 2019, a tropical cyclone in the south-west Indian Ocean led to extensive flooding across several countries. Because the cyclone flooded areas and caused damage, many people faced a very high risk of cholera. Once the natural disaster had happened, cholera outbreaks were reported in many different places. Soon afterwards the disease had spread broadly and affected large numbers of people.
(a)[1]

Name the bacterial pathogen responsible for cholera.

(b)[3]

Suggest and explain why the people affected by the cyclone were at serious risk of cholera.

(c(i))[3]

Doxycycline is one of the main antibiotics used to treat cholera. Doxycycline enters the pathogen and attaches to one of the subunits of the bacterial ribosome. This stops the bacterial cell from growing and reproducing. Suggest and explain how binding of doxycycline to ribosomes stops growth of the bacterial cell.

(c(ii))[1]

Penicillin, which was once prescribed to treat cholera, works differently from doxycycline. State which part of the bacterial cell is affected by penicillin.

(d)[4]

Mozambique was among the countries severely affected by the cyclone. To try to stop a larger rise in cholera cases, two separate measures were used: • Around $900\,000$ doses of the oral cholera vaccine were delivered to Mozambique, and a mass vaccination programme was arranged. • Medical centres were established in Mozambique to care for people with cholera. Suggest and explain how the two different approaches helped to prevent a greater number of cases of cholera from occurring.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: Vibrio\ cholerae

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