# Explain why the cells produced by meiosis must have half the number of chromosomes compared to the parent cell.

> WJEC GCSE Biology (Wales) — 2.2.1 Mitosis and meiosis · Explain · 4 marks

> Sexual reproduction in humans involves the fusion of a sperm cell and an egg cell to form a fertilised egg called a zygote.

## Mark scheme (4 marks)

1. Meiosis produces gametes (sperm and egg cells)
2. At fertilisation, a sperm and egg cell fuse / join together
3. If gametes were not haploid, the zygote would have double the normal chromosome number
4. Having half the chromosome number (haploid) in each gamete means the zygote has the correct / normal chromosome number (diploid) after fertilisation

## Key terms

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

## 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)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-the-cells-produced-by-708db634) · Published by Druglandscape Ltd.