Explain how bacteria cause disease in the human body.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Bacteria release toxins that damage cells or tissues or interfere with normal body processes. The toxins cause cell injury and inflammation, leading to symptoms such as fever, pain or tissue damage. Bacteria also multiply rapidly inside the host, increasing the amount of toxin and the number of cells that can cause damage. The combined effect of toxin production and bacterial proliferation results in the clinical signs of disease.
Examiner tips
- Use the word ‘release’ or ‘produce’ for toxins, then explain the effect on cells. Mention rapid multiplication as a separate point. Link symptoms directly to the damage caused. Keep each point short and to the point. Use UK spelling and correct terminology.
Common mistakes
- Confusing bacterial infection with viral infection.
- Failing to mention toxin production or rapid multiplication.
Mark scheme (4 marks)
- Bacteria release/produce toxins
- Toxins damage cells/tissues OR interfere with normal body processes
- Bacteria multiply/reproduce rapidly (inside the body/host)
- This leads to symptoms of disease / damage causes symptoms such as fever, pain or tissue damage
Key terms in this question
Related
- All Eduqas GCSE Biology revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →