THE GENETIC CODE

• WHAT IS THE GENETIC CODE?

  each sequence of 3 DNA bases (triplet) that code for a specific AA
• WHAT ARE THE FEATURES OF THE GENETIC CODE?

  degenerate, universal, non-overlapping
• WHAT DOES IT MEAN TO BE DEGENERATE?

  each AA is coded for by more than one triplet of bases
• EVIDENCE OF THE GENETIC CODE BEING DEGENERATE?

  64 possible combinations of triplet but only 20 AAs
• WHAT IS THE ADVANTAGE OF DEGENERACY?

  if a point mutation occurs, there is still a possibility that the new triplet codes for the same AA

  -> therefore the mutation will have no effect
• WHAT DOES IT MEAN FOR THE GENETIC CODE TO BE UNIVERSAL?

  same triplet of bases codes for the same AA in all organisms
• WHAT DOES IT MEAN FOR THE GENETIC CODE TO BE NON-OVERLAPPING?

  each base in a gene is only part of one triplet and therefore each codon/ triplet is read as a discrete unit
• WHAT IS THE ADVANTAGE OF THE GENETIC CODE BEING NON-OVERLAPPING?

  if a point mutation occurs, it will only affect one codon and therefore only one AA