# A student extracts DNA from a sample of kiwi fruit cells. During the extraction, detergent is added to the cells. The student observes that the extracted DNA forms a white, stringy precipitate. Explain why DNA is found in the nucleus of the kiwi fruit cells and describe the relationship between nucleotides, genes and chromosomes.

> Edexcel GCSE Biology (1BI0) — 3.3 DNA structure · Explain · 4 marks

> DNA can be extracted from fruit cells using a simple laboratory procedure. Detergent is added to disrupt the cell membranes, releasing the cell contents.

## Mark scheme (4 marks)

1. DNA is found in the nucleus because it is carried on chromosomes, which are located in the nucleus
2. Nucleotides are the monomers / building blocks that make up DNA
3. A gene is a length of DNA that codes for the production of a specific protein
4. A chromosome is a long, coiled molecule of DNA that carries genetic information in the form of genes / chromosomes contain many genes

## Key terms

- [nucleotides](https://www.gradenine.co.uk/glossary/nucleotides)
- [gene](https://www.gradenine.co.uk/glossary/gene)
- [chromosome](https://www.gradenine.co.uk/glossary/chromosome)
- [nucleus](https://www.gradenine.co.uk/glossary/nucleus)
- [DNA](https://www.gradenine.co.uk/glossary/dna)

## 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/a-student-extracts-dna-from-a-97c31940) · Published by Druglandscape Ltd.