DNA Structure (Edexcel IGCSE Biology)

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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

DNA double helix formation, downloadable AS & A Level Biology revision notes

The structure of DNA and complementary base pairs

Examiner Tip

You are expected to know the names of each base so do make sure you use these appropriately in exam answers, rather than just relying on the abbreviated letters.

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Lára

Author: Lára

Expertise: Biology Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.