Some diseases can be prevented by vaccination, while others are treated using antibiotics. Describe how the body responds when a vaccine is given, and explain why completing a full course of antibiotics is important.

Eduqas GCSE Biology — 3.3 Treating, curing and preventing disease · Describe and Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

The vaccine contains antigens (from dead or weakened pathogens or isolated proteins). These antigens are recognised by the immune system and white blood cells/lymphocytes produce specific antibodies. The response also creates memory cells, so if the person is later exposed to the same pathogen the immune system reacts faster and more strongly.

Completing a full course of antibiotics is important because it ensures that all of the bacteria are killed. If the treatment is stopped early, some bacteria may survive and can develop resistance, making future infections harder to treat.

Examiner tips

  • Use the word "antigens" and "antibodies" – examiners look for these terms.
  • Mention memory cells to show understanding of long‑term immunity.
  • Explain that stopping antibiotics early can lead to resistance – this is a key point.
  • Keep the answer concise – 4 marks, so two points for each part.

Common mistakes

  • Using vague terms like "immune system" without specifying antibodies or memory cells.
  • Claiming that vaccines kill the pathogen instead of stimulating an immune response.
  • Saying antibiotics are important because they are ‘strong’ but not explaining resistance or complete eradication of bacteria.

Mark scheme (4 marks)

  1. The vaccine contains antigens (from dead/weakened pathogens or isolated proteins)
  2. White blood cells / lymphocytes produce antibodies specific to those antigens / immune response is triggered
  3. Memory cells are produced / the immune system has a faster / stronger response if infected with the same pathogen in future
  4. Completing the full course of antibiotics ensures all bacteria are killed / prevents surviving bacteria developing resistance

Key terms in this question

vaccine · antibiotics

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