Describe how bacteria can spread from one person to another. Give two different methods of transmission in your answer.

Eduqas GCSE Biology — 3.2 Communicable disease · Describe · 4 marks · View as Markdown

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

Model answer (4 marks)

Bacteria can spread from one person to another by
1. Airborne transmission – when an infected person coughs or sneezes, droplets or aerosols containing bacteria are expelled into the air. A susceptible person can inhale these droplets and become infected (e.g. tuberculosis).
2. Direct contact – touching an infected individual or a surface contaminated with bacteria allows the bacteria to be transferred to the skin or mucous membranes, where they can enter the body (e.g. staphylococcal skin infections).

Examiner tips

  • Use the word ‘airborne’ or ‘direct contact’ to show you know the methods.
  • Give a clear example of a disease for each method.
  • Show the route of spread – e.g. ‘coughing releases droplets’.”]
  • common_mistakes

Mark scheme (4 marks)

  1. Bacteria can spread through the air via droplets / aerosols (e.g. when sneezing or coughing)
  2. Correct elaboration of first method OR named example of a disease spread this way
  3. Bacteria can spread through direct contact / touching an infected person or contaminated surface
  4. Correct elaboration of second method OR named example of a disease spread this way

Key terms in this question

bacteria · transmission

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