# Explain how the structure of a nucleosome relates to the packaging of DNA in eukaryotic cells.

> IB DP Biology Standard Level (2023 syllabus) — A1.2 Nucleic acids · Explain · 4 marks

## Mark scheme (4 marks)

1. A nucleosome consists of DNA wrapped around a core of histone proteins
2. This association with histones allows a long DNA molecule to be compacted/shortened considerably
3. Nucleosomes are further coiled/folded into higher-order chromatin fibres, increasing the degree of compaction
4. This packaging is necessary because eukaryotic cells contain very large amounts of DNA that must fit within the nucleus

## Key terms

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

## 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-the-structure-of-a-9fd9d515) · Published by Druglandscape Ltd.