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14 Cards in this Set
- Front
- Back
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mutant
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organism w/ an altered base sequence in one or more genes
usually has phenotypic diff. from wild type |
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wild type
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unaltered "wild" organism
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parental strain
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the parent from which a mutant strain came- may be wild type or a mutant itself (more likely)
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mutations defined by to types
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defined by genotype
1. point mutations: silent to loss of function 2. rearrangements: deletions, duplications, inversion or insertions = large changes |
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mutagens
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DNA damage inducing chemical and physical agents
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transposons
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mobile genetic elements that move w/in chromosomes
present in all organisms may carry additional genes (antibiotic resistance) |
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how do transposons move?
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encode a transposase to mediate movement
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How are transposons reversible mutations
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some excise precisely and loss of function is regained
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how are transposons permanently inactive?
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they leave DNA behind, usually a copy of themselves but never pick up DNA
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What are transposons useful for?
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can create library of mutants b/c need to be signaled to be told to "hop"
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What are 3 methods of screening if seeking 1 location for mutation
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Penicillin
Replica plating patch plating |
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patch plating screens
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similar to replica plating
still look for dead guys touch between two diff. conditions using a grid |
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penicillin method
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put culture in environment in which wild-type cells can grow but desired mutant cells cannot
add penicillin to cause live bacteria's cell wall to lyse doesn't effect dead desire mutants b/c not growing take penicillin and add nutrients to mutants to grow |
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replica plating
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pressed down on plate w/ both wild-type and mutant colonies w/ fabric
place FIRST on plate containing amino acid and then one lacking a.a. compare plates to see colonies that do not grow under certain conditions (WANT THESE!) |
