# A patient is diagnosed with a bacterial infection and is prescribed a course of antibiotics. A friend advises the patient to stop taking the antibiotics as soon as they feel better, rather than completing the full course. Explain why it is important that the patient completes the full course of antibiotics.

> Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 5.4 Antibiotics and resistance · Explain · 5 marks

> Antibiotic resistance is an increasing global health concern. Bacteria can become resistant to antibiotics through natural selection.

## Mark scheme (5 marks)

1. Some bacteria in the infection may be naturally resistant to the antibiotic
2. If the course is stopped early, not all bacteria are killed / some survive
3. The surviving resistant bacteria reproduce / pass on the resistance gene to offspring
4. Natural selection leads to an increase in the proportion of resistant bacteria in the population
5. A new / different antibiotic would be needed to treat the resistant strain, which may not be available / effective

## Key terms

- [antibiotic](https://www.gradenine.co.uk/glossary/antibiotic)
- [bacteria](https://www.gradenine.co.uk/glossary/bacteria)

## Related

- [Revision notes for Edexcel A-Level Biology A: Salters-Nuffield (9BN0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-patient-is-diagnosed-with-a-96234852) · Published by Druglandscape Ltd.