# Describe the structure of DNA and explain why the base-pairing rules are important for storing genetic information.

> Eduqas GCSE Biology — 7.1 The genome and gene expression · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. DNA is made up of two strands wound into a double helix
2. The strands are held together by bases, which are paired in a specific way (A with T, and C with G)
3. The sequence of bases along a strand forms a genetic code / acts as a code for making proteins
4. Specific base pairing ensures that when DNA is copied, both new strands carry the same genetic information as the original

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