Vaccination, HIV and antibioticsAQA A-Level Biology: Mind map

Exam questions on Vaccination, HIV and antibiotics

1. A town has a population of 40 000. Health officials have vaccinated 95% of the population against measles. Measles spreads easily from person to person by droplets. Babies under one year, and people whose immune systems are suppressed by drugs, cannot be given the vaccine.
   Explain how a high vaccination rate protects the babies in the town from measles.2 marks
2. A traveller is bitten by a dog in a region where rabies is common. At the clinic she is given an injection of human rabies antibodies, and she is also given a course of rabies vaccine.
   Explain why the injected antibodies protect the traveller for only a short time.2 marks
3. A man diagnosed with HIV infection had a helper T cell count of 800 cells per mm³ of blood. Eight years later, without treatment, the count had fallen to 150 cells per mm³ and he was suffering from recurrent pneumonia and tuberculosis.
   Describe how HIV enters and replicates in a helper T cell.3 marks