# Explain why DNA replication must occur before mitosis and describe one consequence if replication failed to occur.

> IB DP Biology Standard Level (2023 syllabus) — D1.1 DNA replication · Explain · 4 marks

## Mark scheme (4 marks)

1. DNA replication ensures each daughter cell receives a complete / full copy of the genetic information
2. Mitosis separates the duplicated chromosomes so one copy goes to each daughter cell; without prior replication there is insufficient DNA to distribute
3. If replication failed, daughter cells would lack essential genes / would be missing genetic information
4. This would prevent production of essential proteins / disrupt cellular function / cause cell death or inability of the organism to grow and repair tissues

## Key terms

- [DNA replication](https://www.gradenine.co.uk/glossary/dna-replication)
- [mitosis](https://www.gradenine.co.uk/glossary/mitosis)

## 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-why-dna-replication-must-occur-00f9bb7e) · Published by Druglandscape Ltd.