The genetic code

• Sequence of codons in mRNA

  1. Each codon codes for a specific amino acid

  2. Sequence of codons—> sequence of amino acids
• Genetic code


  • Non-overlapping - codons do not share their bases
• U


  A
• C


  G
• A


  T
• G


  C
• A


  U
• Degenerate code


  The genetic code is degenerate - there are 64 possible codons but only 20 amino acids, so some amino acids are coded for by more than one codon
• Not all codons code for amino acids, some are start or stop signals at the start or end of mRNA
• Universal code


  • The same codons code for the same amino acids in all organisms, suggesting common evolutionary ancestry