# DNA is a polymer that forms a double helix structure. Describe the structure of DNA and explain how it is replicated inside a cell.

> Eduqas A-Level Biology — 1.5 Nucleic acids and DNA replication · Describe and Explain · 5 marks

## Mark scheme (5 marks)

1. DNA is made of two strands twisted around each other (forming a double helix)
2. DNA contains bases that pair in a complementary way
3. The two strands of the double helix unwind / separate
4. Each original strand acts as a template for a new complementary strand
5. Two identical copies of DNA are produced / each new molecule contains one original strand and one new strand

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Biology](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/dna-is-a-polymer-that-forms-50f48f19) · Published by Druglandscape Ltd.