Mutations

• Mutation - is a change in the DNA base sequence.
• Things which increase the risk of mutation:

  • Carcinogens ( a group of harmful chemicals, such as tar from cigarettes)
  • Radiation
• How mutations occur:

  • A change in the base occurs.
  • So amino acids which the triplet codes for will be different.
  • As a result, the overall amino acid sequence would be different, so different protein would be produced.
  • meaning protein could have different shape or function.
• Types of mutations:

  • Substitutions
  • Insertions
  • Deletions
• Substitution mutation is when one of the bases has changed for another random base.
• Insertion mutations is when an extra base is inserted into sequence. Its effect is much bigger as it causes each base after is to shift along, so every triplet will be changed.
• Deletion mutations is when one of the bases is deleted from the sequence. It causes the other bases to shift as well, therefore different triplets are made.