Describe - Gene Alteration


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miscoded mRNA, mRNA mutations, frameshift mutation, base-pair substitutions, missense mutation, nonsense mutation, silent mutation, mutagens, uv light mutagen, nitrous acid mutagen, base analog mutagens

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Describe - Gene Alteration

  1. 1. Describe: gene alteration b.stev
  2. 2. chromosomes may alter a b n o r m a l ly - this is said to be a: mutation > It causes miscoded mRNA mRNA codes for proteins that gives functions to the bacteria’s processes, thus alteration to this changes how the bacteria can operate correctly some have little effect/ others, contained within codons that would aid survival of the bacteria: - defence toxin production against competition - digestion enzyme change to the environment OR various purposes that effects their abilities (Campbell N. A, Reece J. B, 2005)
  3. 3. A U G A A G U U U G G U U A A Met Lys Phe Gly STOP U instead of a C Gly CODONS : GGU GGC GGA GGG
  4. 4. MISSENSE MUTATION: makes an amino acid, though the specific amino acid that was wanted within the sequence of the mRNA has changed A U G A A G U U U A G U U A A Met Lys Phe Ser STOP A instead of a G change in the amino acid
  5. 5. NONSENSE MUTATION : codon changes to the codes for a STOP codon Results: a shorter protein is made that is usually non-functional to the bacteria A U G U A G U U U G G U U A A Met STOP U instead of A (Campbell N. A, Reece J. B, 2005)
  6. 6. HAS a disastrous effect as it causes the sequence to become,’ out of line ,’ & as such results in extensive missense mutations RESULTS: proteins that are probably non-functional and/ or prematurely terminate in sequence INSERTION/ DELETION OF PAIRS
  7. 7. A U G A A G U U U G G U U A A Met Lys Phe Gly STOP A G INTENDED SEQUENCE insertion
  8. 8. mutagens UV light - causes thymine dimers in chemical bonding: DNA RESULTS: inability to insert correct bases when transcribed in process to the mRNA NOTE: this is how UV light can be used to kill bacteria Chemical OR Physical agent that causes a mutation (Pommerville J.C, 2004)
  9. 9. A C A A C C T G T T G G normal DNA A C A A C C T G T T G G abnormal DNA UV light: chemical bonding change
  10. 10. Nitrous acid THE [ A ]: adenine base ; in DNA converts into a hypoxanthine molecule(s) RESULTS: no existance of an, [ A - T ] pair instead; [ hypoxantine& C ] pair <ul><li>entire purpose is thereafter altered </li></ul>
  11. 11. <ul><li>CHEMICAL structure is similar </li></ul><ul><li>resembles the bases of DNA </li></ul>Replaces the, [ T ]: thymine base ; DNA AGAIN – entire purpose is then altered Base analog ie: chemical, 5-bromouracil
  12. 12. other chemicals effect DNA in some way ie: benzopyrene (in soot) aflatoxin heavy smoke Different effects (Pommerville J.C, 2004)
  13. 13. Bibliography Campbell N. A, Reece J. B. (2005). Biology (7th ed.) . San Francisco: Benjamin Cummings Pommerville J.C. (2004). Alcamo’s – Fundamentals of Microbiology (7 th ed.). Massachusetts: Jones and Bartlett.