Mutations

• What is a mutation?

  • A change in the base sequence of the DNA
• What are the 3 types of mutations?

  • Insertion
  • Substitution
  • Deletion
• How does a substitution mutation work?

  • One base letter is changed
  • This changes that particular codon which changes the amino acid it codes for in the sequence
• How does an insertion mutation work?

  • A base is inserted into the code
  • This changes the way the code is read as they are read in triplets
  • It might change all amino acids coded after the insertion
• How do deletion mutations work?

  • A base is deleted from the code
  • This changes the way the code is read
  • It may change all amino acids coded after the deletion
• What do changes in the DNA structure affect?

  • The way it folds so therefore its structure
  • Most mutations don't change the protein or do so slightly
• What are some serious consequences mutations can have?

  • Change the shape of a protein
  • E.g.. Ezymes active site is no longer complimentary to a substrate
  • Structural protein might lose its shape
  • Mutations in non coding parts of DNA can change how genes are expressed
•  Non-coding parts of DNA can switch genes on and off, so variations in these areas of DNA may affect how genes are expressed.