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Macromolecules
Key Concepts

Nucleic Acids III:
DNA

 		DNA molecules are amongst the largest of the macromolecules. Two polynucleotide chains twist around one another in a double helix. This molecule plays a vital role in information storage and use.

    Key concepts:
  • nucleotides built around the deoxyribose sugar are used in this molecule.
  • this molecule is called deoxyribonucleic acid or DNA.
  • the four nitrogenous bases used in DNA are, adenine, guanine, cytosine and thymine.
  • two parallel chains of linked deoxyribonucleic acids twist around one another in a double helix.
  • the nitrogenous bases extend into the center of the helix.
  • a base from one strand pairs with a base on the opposite strand.
  • an adenine base always pairs with a thymine base, and a guanine base always pairs with a cytosine base; often represented as A:T and G:C.

Science@a Distance
© 2001, Professor John Blamire