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33 Cards in this Set

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  • Back
Who developed the concept of the complementation test?
Seymour Benzer
What was Seymour Benzer doing when he developed the concept of the complementation test?
Examining rll mutants of phage T4 in the 1950s.
What was Seymour Benzer able to show ursing the complementation test?
He was able to show that the rll phenotype is conferred by two closely linked, but functionally independent genes.
How does complementation work?
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.
Why can complementation tests be rapidly carried out with yeast?
Yeas has both a stable haploid and diploid phase. (It's most straightforward to think about haploids together to make diploids.)
What is the purpose of complementation?
To determine if mutations are in the same genes or different genes.
Can copmlementation be used for recessive mutations, dominant mutations, or both?
Only recessive mutations.
What are the linked genes in this experiment?
HIS4A, 4B, and 4C
Under what forms are yeast haploid/diploid?
usually function as mitotically reproducing diploids, but starvation can induce yeast to undergo meisosi and sporulation to form haploid spores
What will a single meiosis produce in yeast?
Two different mating types: a and alpha, (two of each type)
How does the mating of a and alpha work?
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."
What are we crossing in this lab?
Six unknown strains of His- mutants of mating type "alpha" and six known strains of "a" His- mutants
What did George Beadle isolate?
Genetic mutations in the filamentous fungi Neurospora crassa that he showed were defective only in the synthesis of a single vitamin or amino acid.
What did the results of Beadle's experiment show?
That each mutation produced a single defective enzyme, (the one-gene, one-enzyme theory)
What are the Neurospora mutants that we are working with defective in?
Arginine syntehsis
Who applied Beadle's strategy of mjtant analysis to dissect the process of early embryonic development in rosophila?
Christiane Nüsslein-Volhard
Who used mutant analysis to dissect the process of programmed cell death in the nematode worm C. elegans?
Bob Horvitz
What are the doubling times of yeast, neurospora, and bacteria?
Yeast: 90 minutes
Neurospora: 140 minutes
Bacteria: 20 minutes
How are liquids and many solids commonly sterilized?
With high heat and pressure in na autoclave.
How are plastic Petri plates sterilized?
Gamma irradiation
How do you avoid air contamination?
Performed within 12 inches of a Bunsern burner - the flame creates an updraft that prevents contaminants from faling into the workspace
Where are the 6 parallel lines drawn on each plate?
The bottom of each plate, not the lid
What type of plates do you obtain and how many?
Two YEPD plates, (Yeast Extract, Peptone, and Dextrose)
What do you number the lines on each plate?
1-6 on plate one and 1-7 on plate 2
What are the toothpicks used for?
To transfer yeast from the stock plates to experimental plates
What are the known his mutagens?
1. a his1
2. a his2
3. a his3
4. a his4B
5. a his5
6. a his7
What does the lab staff do with your plates?
Transfer them in 30ºC for 2 days, then 4ºC until we return
What should we obtain the second week?
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
How should the replica plating block be placed on the benchtop?
So that the solid end faces up, (not the hollow end)
What should you do with the velvet foil packet?
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
What do you do after the velvet has be secured over the replica plating block?
Invert plate 1 on the velvet and press down gently so that cells are transferred to the velvet.
How should plate II be placed on the replicating block?
So that they are perpendicular to the 1-stripes.
What intermediates do the plates for arginine biosyntehsis of Neurospora crassa contain?
Nothing, Ornithine, CItruline, or Arginine