DNA Structure (Edexcel IGCSE Biology (Modular): Unit 2): Revision Note

The Structure of DNA

• DNA, or deoxyribonucleic acid, is the genetic material found in the nucleus of a cell

• DNA, is a polymer made up of two strands coiled around to make a double helix

• The strands are formed from a sugar phosphate backbone with bases:

  • Adenine (A)

  • Thymine (T)

  • Guanine (G)

  • Cytosine (C)

• The bases are bonded together by complementary base pairing

  • A pairs with T

  • G pairs with C

•  Cell division and protein synthesis both rely on these base-pairing rules because each half of the DNA double helix acts as a template to be copied to create a completely new double helix

The structure of DNA and complementary base pairs