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33 Cards in this Set
- Front
- Back
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Who developed the concept of the complementation test?
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Seymour Benzer
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What was Seymour Benzer doing when he developed the concept of the complementation test?
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Examining rll mutants of phage T4 in the 1950s.
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What was Seymour Benzer able to show ursing the complementation test?
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He was able to show that the rll phenotype is conferred by two closely linked, but functionally independent genes.
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How does complementation work?
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Crossing two haploid mutants with the same mutant phenotype, such as a specific amino acid requirement, and determining if hte resulting diploid has the same phenotype.
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Why can complementation tests be rapidly carried out with yeast?
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Yeas has both a stable haploid and diploid phase. (It's most straightforward to think about haploids together to make diploids.)
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What is the purpose of complementation?
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To determine if mutations are in the same genes or different genes.
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Can copmlementation be used for recessive mutations, dominant mutations, or both?
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Only recessive mutations.
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What are the linked genes in this experiment?
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HIS4A, 4B, and 4C
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Under what forms are yeast haploid/diploid?
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usually function as mitotically reproducing diploids, but starvation can induce yeast to undergo meisosi and sporulation to form haploid spores
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What will a single meiosis produce in yeast?
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Two different mating types: a and alpha, (two of each type)
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How does the mating of a and alpha work?
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haploid yeast emit pheromones that attract yeast of the opposite mating type, so a and alpha grow in the direction of the other mating type, forming structures called "schmoos."
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What are we crossing in this lab?
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Six unknown strains of His- mutants of mating type "alpha" and six known strains of "a" His- mutants
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What did George Beadle isolate?
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Genetic mutations in the filamentous fungi Neurospora crassa that he showed were defective only in the synthesis of a single vitamin or amino acid.
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What did the results of Beadle's experiment show?
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That each mutation produced a single defective enzyme, (the one-gene, one-enzyme theory)
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What are the Neurospora mutants that we are working with defective in?
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Arginine syntehsis
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Who applied Beadle's strategy of mjtant analysis to dissect the process of early embryonic development in rosophila?
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Christiane Nüsslein-Volhard
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Who used mutant analysis to dissect the process of programmed cell death in the nematode worm C. elegans?
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Bob Horvitz
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What are the doubling times of yeast, neurospora, and bacteria?
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Yeast: 90 minutes
Neurospora: 140 minutes Bacteria: 20 minutes |
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How are liquids and many solids commonly sterilized?
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With high heat and pressure in na autoclave.
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How are plastic Petri plates sterilized?
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Gamma irradiation
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How do you avoid air contamination?
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Performed within 12 inches of a Bunsern burner - the flame creates an updraft that prevents contaminants from faling into the workspace
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Where are the 6 parallel lines drawn on each plate?
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The bottom of each plate, not the lid
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What type of plates do you obtain and how many?
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Two YEPD plates, (Yeast Extract, Peptone, and Dextrose)
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What do you number the lines on each plate?
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1-6 on plate one and 1-7 on plate 2
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What are the toothpicks used for?
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To transfer yeast from the stock plates to experimental plates
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What are the known his mutagens?
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1. a his1
2. a his2 3. a his3 4. a his4B 5. a his5 6. a his7 |
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What does the lab staff do with your plates?
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Transfer them in 30ºC for 2 days, then 4ºC until we return
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What should we obtain the second week?
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1. Plates from last week
2. Two fresh YEPD plates 3. Foil packet containing sterile velvet 4. Replica plating block, (a plastic cylinder about the size of a sda can) 5. Plastic ring that fits around the replica plating block |
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How should the replica plating block be placed on the benchtop?
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So that the solid end faces up, (not the hollow end)
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What should you do with the velvet foil packet?
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Touching only the corners and the no-uzzy side, place the velvet on the replica plating block so that the fuzzy, (sterile), side is facing up, then slide the plastic ring over the velvet to secure it
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What do you do after the velvet has be secured over the replica plating block?
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Invert plate 1 on the velvet and press down gently so that cells are transferred to the velvet.
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How should plate II be placed on the replicating block?
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So that they are perpendicular to the 1-stripes.
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What intermediates do the plates for arginine biosyntehsis of Neurospora crassa contain?
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Nothing, Ornithine, CItruline, or Arginine
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