CAIE A Level Biology 9700 · Infectious diseases
A patient is diagnosed with both a bacterial throat infection (caused by Streptococcus pyogenes) and a viral respiratory infection (caused by influenza virus). The doctor prescribes a course of penicillin.
(a) Explain why penicillin is effective against the bacterial infection but has no effect on the viral infection. (b) Discuss the consequences of antibiotic resistance and the steps that can be taken to reduce its impact.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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