Biology 9700 · AS & A Level · Antibiotics

Antibiotics — practice question

Mammals have a circulatory system with double circulation.
(a(i))[1]

Explain what the term double circulation means.

(a(ii))[3]

Fig. 3.1 is a photograph of one valve in the mammalian heart. Identify the structures labelled A in Fig. 3.1 and describe their function during the cardiac cycle.

(b(i))[2]

With reference to Table 3.1, explain why using gentamicin and penicillin G together lowers the risk of antibiotic resistance developing when treating endocarditis.

(b(ii))[3]

Describe how the bacteria that cause endocarditis could become resistant to gentamicin.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Double circulation: blood passes through the heart twice for each complete circuit

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI