Mutations

• Substitution

  One base is substituted with another
• Deletion

  One base is deleted
• What happens to the base sequence of DNA when a mutation occurs?

  The sequence of amino acids it codes for will be altered

  Changes the tertiary structure of the protein
• Degenerate nature of the genetic code

  Some amino acids are coded for by more than one DNA triplet
• Substitution mutations vs deletion mutations (3)

  Substitution mutations wont always leads to changes in the amino acid sequence but deletion ALWAYS will

  The deletion of a base will change the number of bases present - leading to a frameshift
• Mutagenic agents

  Mutagenic agents can increase the rate of mutation:

  Mutations occur spontaneously

  • UV radiation
  • Ionising radiation
  • Chemicals
  • Viruses