# Explain how phagocytes destroy pathogens that have entered body tissues.

> IB DP Biology Standard Level (2023 syllabus) — C3.2 Defence against disease · Explain · 4 marks

## Mark scheme (4 marks)

1. Phagocytes are attracted to the site of infection by chemical signals (chemotaxis/cytokines/chemokines) released by damaged or infected cells.
2. Phagocytes engulf pathogens by endocytosis, forming a phagosome (vacuole) around the pathogen.
3. Lysosomes fuse with the phagosome, releasing hydrolytic (digestive) enzymes into the phagolysosome.
4. The hydrolytic enzymes break down / digest the pathogen, destroying it; products may be expelled from the cell or used by the phagocyte.

## Key terms

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

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](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-phagocytes-destroy-pathogens-that-2a6039f2) · Published by Druglandscape Ltd.