Nucleic acids


  • Nucleic acids include the macromolecules DNA and RNA which are important in the genetic regulation of protein production and cellular reproduction.
  • The subunits if these macromolecules are known as nucleotides and consist of a sugar (deoxyribose in the case of DNA and ribose in the case of RNA), a Phosphate group and one of four bases.
  • These four bases are: Adenine, Cystosine, Guanine and Thymine. Thymine is substituted for Uridine in RNA.


    • In both DNA and RNA, the nucleotides are polymerised in a strand through phospodi-ester bonds between the sugar back-bone.
    • These single strands can form a double stranded molecule through hydrogen bonds between pairs of nucleotides.
    • Guanine and Cytosine can form three hydrogen strands while adenine and thymine (uracil) can form two hydrogen bonds.
    • Thus Guanine always pairs with cytosine and adenine always pairs with thymine.
    • This form the Basis of the primary functions of the nucleic acids.