Mutations

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  • MUTATIONS
    • A mutation is a change in the amount of or arrangement of the genetic material in a cell
      • Chromosome mutations involve changes to the structure of chromosomes and/or to their number
      • DNA mutations are changes to genes due to changes in nucleotide base sequences
    • A mutation is a random change to genetic material, they may occur during DNA replication, before nuclear division during mitosis or meiosis
      • Mutations that are associated with MITOSIS are somatic mutations are are NOT passed on to offspring
        • Somatic mutations however may contribute to the ageing  process and may lead to cancer
      • Mutations associated with meiosis and gamete formation CAN BE inherited by offspring
    • Certain substances called mutagens may cause mutations
      • Tar
      • UV light
      • X Rays
      • Gamma Rays
    • There are two main classes of DNA mutation
      • Point mutations in which one base pair replaces another, also known as substitutions
      • Insertion mutations or deletion mutations in  which one or more nucleotide pairs are inserted or deleted from a length of DNA causing a frameshift
    • Many genetic diseases are the result of DNA mutations, such as sickle cell anaemia and cystic fibrosis
      • Cystic fibrosis - deletion
      • Sickle cell anaemia - substitution
      • Growth promoting genes are called photo oncogenes
        • They may be changed into oncogenes by a point mutation that alters the ability of the protooncogene to he switched off
          • Oncogenes promote unregulated cell division
  • CAG
    • Gln
  • TTT
    • Phe
  • CAG
    • Gln
  • TTT
    • Phe
  • TAA
    • STOP
  • CGC
  • ATG
    • Met
    • Point mutation - silent mutation
  • CAG
    • Gln
  • CAG
    • Gln
  • TTT
    • Phe
  • TTG
    • Leu
  • CGC
    • Arg
  • ATG
    • Met
    • Point mutation - frameshift
  • CAG
    • Gln
  • CAG
    • Gln
  • TTT
    • Phe
  • GCA
    • Ala
  • ATC
    • Lle
  • CC
  • Many genetic diseases are the result of DNA mutations, such as sickle cell anaemia and cystic fibrosis
    • Cystic fibrosis - deletion
    • Sickle cell anaemia - substitution
    • Growth promoting genes are called photo oncogenes
      • They may be changed into oncogenes by a point mutation that alters the ability of the protooncogene to he switched off
        • Oncogenes promote unregulated cell division

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