# Explain how the immune system responds when a pathogen enters the bloodstream for the first time.

> WJEC GCSE Biology (Wales) — 2.6.1 Pathogens and disease · Explain · 4 marks

## Mark scheme (4 marks)

1. White blood cells detect the pathogen / recognise it as foreign
2. Antibodies are produced that are specific to the antigens on the pathogen
3. The antibodies destroy / neutralise / clump together the pathogens
4. Memory cells are produced so the response is faster if the same pathogen is encountered again

## Key terms

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

## Related

- [Revision notes for WJEC GCSE Biology (Wales)](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/explain-how-the-immune-system-responds-ab97cd21) · Published by Druglandscape Ltd.