Vaccination, HIV and antibioticsAQA A-Level Biology: Flashcards
What these 13 flashcards ask
- What does a vaccine contain?
- How does a vaccine give protection?
- What is herd immunity?
- Who relies on herd immunity?
- What is active immunity?
- What is passive immunity?
- Give two examples of passive immunity.
- What does HIV contain?
- Which cells does HIV infect?
- What does reverse transcriptase do?
- How does HIV cause AIDS?
- Why are antibiotics ineffective against viruses?
- Name two ethical issues with vaccines.
Exam questions on Vaccination, HIV and antibiotics
- 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
- 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
- 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
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).