# Explain how B-lymphocytes protect the body after a pathogen enters the bloodstream for the second time.

> Edexcel GCSE Biology (1BI0) — 5.2 Pathogens and immunity · Explain · 4 marks

> When a person is exposed to the same pathogen more than once, their immune system responds much more rapidly and effectively than during the first infection.

## Mark scheme (4 marks)

1. B-lymphocytes produce antibodies specific to the antigen on the pathogen
2. Memory cells / memory B-lymphocytes are retained after the first exposure
3. On second exposure, memory cells divide rapidly and produce large quantities of antibodies quickly
4. The pathogen is destroyed before symptoms develop / the person does not become ill

## Key terms

- [B-lymphocyte](https://www.gradenine.co.uk/glossary/b-lymphocyte)

## Related

- [Revision notes for Edexcel GCSE Biology (1BI0)](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-b-lymphocytes-protect-the-body-2b80c246) · Published by Druglandscape Ltd.