Immunity and vaccinationEdexcel A-Level Biology B: Subtopic test

1. 1
   A health visitor explains to new parents that their newborn baby is protected against several infections for the first few months of life. The protection comes from antibodies that crossed the placenta from the mother's blood before birth and from antibodies present in her breast milk.

   (a)

   What type of immunity do the antibodies from the mother give the baby?

   [1 mark]

   • ANatural active immunity
   • BNatural passive immunity
   • CArtificial active immunity
   • DArtificial passive immunity

   (b)

   Which statement about the protection the baby receives from these antibodies is correct?

   [1 mark]

   • AIt starts immediately because the antibodies are already made
   • BIt is long-lasting because memory cells are passed to the baby
   • CIt requires the baby's B cells to be exposed to the antigen
   • DIt is produced by plasma cells in the baby's blood

   (c)

   Explain why the protection from the mother's antibodies lasts only a few months.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A school nurse is reviewing uptake of the MMR vaccine, which protects against measles, mumps and rubella. Measles is highly infectious and about 95% of a population must be immune to prevent outbreaks. In one town, 78% of children have been vaccinated. A small number of pupils cannot be vaccinated because they are receiving chemotherapy.

   (a)

   What type of immunity does the MMR vaccine give a vaccinated child?

   [1 mark]

   • ANatural active immunity
   • BNatural passive immunity
   • CArtificial active immunity
   • DArtificial passive immunity

   (b)

   Which conclusion is best supported by the information about the town?

   [1 mark]

   • AHerd immunity has been achieved because most children are vaccinated
   • BMeasles cannot spread because a majority of children are immune
   • COutbreaks are impossible because vaccination prevents all infections
   • DMeasles can still spread because the proportion immune is below the level needed for herd immunity

   (c)

   Explain how a high level of vaccination in a town would protect the pupils who cannot be vaccinated.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A hiker is bitten by a stray dog in a region where rabies occurs. The rabies virus travels slowly along nerves and can take several weeks to reach the brain, after which the disease is almost always fatal. Doctors give the hiker an injection of human rabies antibodies straight away, followed by a course of rabies vaccine over the next few weeks.

   (a)

   Explain why the hiker is given both the rabies antibodies and the rabies vaccine.

   [3 marks]

   (b)

   Describe how the rabies vaccine leads to the production of memory cells in the hiker.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A national health agency reports that uptake of a childhood vaccine against a bacterial disease has fallen from 96% to 84% over ten years, because some parents are worried about side effects. Over the same period cases of the disease have risen, including in babies who are too young to be vaccinated and in children whose immune systems are weakened by medical treatment.

   (a)

   Explain why the fall in vaccine uptake has led to more cases of the disease, including in babies and in children with weakened immune systems.

   [6 marks]

   (b)

   Evaluate whether vaccination is a better way of gaining immunity than recovering from natural infection. Justify your conclusion.

   [6 marks]

   Total for question 4: 12 marks

End of questions