1. Difference between spontaneous and induced mutations + sources for each?
    • Spontaneous: Replication errors, base modifactions (tautomeric shifts), transposable elements
    • Induced: DNA damage from chemicals and radiation, organisms have DNA repair systems to counteract DNA damages
  2. Various types of mutations
    • Transitions: purine for purine (A -> G)
    • Transversions: purine for pyrimidine (A -> C)
    • Deletion/insertion of more than one base
    • Major alteration in chromosomal structure
  3. Various sources of spontatious mutations
    • DNA Polymerase occasionally inserts incorrect nucleotides
    • Tautomeric shifts: allow noncomplementary basepairing (A-C)
    • Deamination: amino group in C or A is converted to uracil (A-T converted to G-C)
    • Depurination: loss of one nitrogenous base in an intact double-helical DNA molecule
  4. UV Radiation: what change to the DNA do they cause, and how are they repaired
    • Cause pyrimidine dimers (typically thymine) that distort DNA conformation.
    • Photoreactive repair (prokaryotes): uses blue light to repair
    • Nucleotide excision repiar (euk): nuclease excises lesion and gap is filled/repaired
  5. Ionizing radiation
    • X rays, gamma rays, cosmic rays
    • Transofrms stable molecules into free radicals which alter DNA
  6. Ames test
    • Salmonella typhimurium used to reveal mutagenic properties of substances.
    • Bacteria are His- and grown on a medium that includes His.  Anything that grows has undergone mutation.  Spontaneous reverts are used as a control
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