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Gene Mutations

Gene Mutations. Essential Question: How do changes in the DNA nucleotide sequence affect the resulting protein?. Mutations. What causes them?. Any mistake or change in DNA sequence. Random or Environment influences – X-rays, UV rays, radioactive materials, chemicals, medications.

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Gene Mutations

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  1. Gene Mutations Essential Question: How do changes in the DNA nucleotide sequence affect the resulting protein?

  2. Mutations What causes them? Any mistake or change in DNA sequence Random or Environment influences – X-rays, UV rays, radioactive materials, chemicals, medications

  3. More about mutations • Can be beneficial, harmless, or harmful • 2 types: Gene & Chromosomal

  4. Chromosomal mutation: affects whole or part of a chromosome Gene mutation: Changes to the bases in the DNA of ONE gene

  5. 1. Gene Mutations • Change in one or more nucleotides • Affects the amino acids and protein produced • 2 types

  6.  Point Mutation • Change in a single base pair in DNA • Ex: The dog bit the CAT The dog bit the CAR

  7. Sickle Cell Anemia

  8. Some Point Mutations are Harmless • What amino acid is represented by the DNA sequence GGA? • What amino acid is represented by the DNA sequence GGC? • This change in the 3rd base of the codon is a point mutation, yet the amino acid would remain the same. Therefore, the protein would NOT be affected.

  9. Some Point Mutations are Harmless • This type of point mutation is called a silent mutation. • Silent Mutations are possible due to the redundancy in the genetic code.

  10.  Frameshift Mutation • Single base pair is added or deleted from DNA • Ex: Cystic Fibrosis

  11. FRAME SHIFT MUTATIONCauses a shift in the “reading frame” the fat cat ate the rat thefatcatatetherat ____________________ INSERTION thefatcataatetherat DELETION thefatcatatetherat the fat cat aat eth era t the fat ata tet her at

  12. Frame shift mutations change every ___________ in the ___________ that follows the shift. Frame shifts can alter a protein so much it is unable to _____________ Amino acid protein FRAME SHIFTS function

  13. Location of the shift is important! AT BEGINNING the fat cat ate the rat AT END the fat cat ate the rat the fac ata tet her at the fat cat ate thr at BEGINNING MUTATIONS AT _____________OF GENEDAMAGE __________ OF THE CODE! MORE

  14. Nonsense Mutations • A point mutation or a shift in the reading frame can sometimes cause a premature STOP codon • This type of mutation is called a nonsense mutation • If the nonsense mutation occurs early in the mRNA sequence, the protein is greatly shortened and most likely non functional

  15. Some mutations are beneficial • Gain-of-function mutations produce a functional protein that results in an entirely new trait • These mutations are usually beneficial and result in an advantage in an organism’s environment • EX: The mutation that resulted in eyesight

  16. Practice – Name that Mutation 1 2 4 3 6 5

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