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28 Cards in this Set
- Front
- Back
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how many genes make a bacteria?
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5,000 genes
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why was bacteria an ideal candidate for genetic research?
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bacteria contain a one chromosome which makes it easy to detect mutations
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Why were auxotrophs used for the study of nutritional mutants?
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study of one gene based on its inability to utilize (or produce) a particular nutrient.
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why was a reversion a problem in bacterial studies?
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a spontaneous mutation would correct its abnormality back to its wild-type form.
when trying to determine mutation rates, reversion was an issue for proper research. |
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how do you decrease the possibility of spontaneous reversion?
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double and triple auxotroph mutant strains were utilized.
Also instead of point mutation (mutation in specific areas of the gene) just delete the whole gene. |
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what's a plasmid?
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extra chromosomal pieces of DNA
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how many nucleotides in a plasmid?
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10,000 nucleotides
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must the plasmid put into cells be compatible?
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yes, you want plasmids that are different from one another, different by origin and replication, no identicals!
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microbial geneticists compare what to strains of bacteria together?
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wild type and mutant
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what does genotype mean
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all the genes
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designated names for genes - general "rules"
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three letter abbreviation in italics
followed by a capital letter |
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designated names for proteins - general 'rules'
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three letter abbreviation
no italics first letter of the three is capital followed by another capital letter |
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phenotypic selection
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use of a growth medium that will inhibit microbes lacking the desired genes.
(streak a culture sensitive to streptomycin antibiotic on a growth agar that contains streptomycin. The colonies that grow are mutants resistant to streptomycin.) |
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phenotypic screening
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everything grow
pick out the 'right thing' |
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replica plating
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photocopying growths and comparing growth
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patching
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transferring colonies to a gridded plate
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lenski's experiment is characterized as what/
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the dullest experiment in the history of science.
trasnfers 0.1 ml of cells to 9.9 ml of fresh medium everyday and has been doing so for the past 20+ years. |
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what did lenski's experiment show?
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evolution is repeatable
cells developed the ability to utilize citrate after 31,000 generations in the medium (wild type E. coi can't do that) |
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esther lederberger experiment
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used replica plating to illustrated spontaneous mutation without selective pressure.
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Luria and delbruck expeirment
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showed variable resistance to phage infection arises in bacteria without selective pressure.
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restriction enzymes are what?
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our enzomatic cutters
they cut DNA at specific sites |
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After restriciton enzymes are cut what happens?
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similar ends of cut are paired and tied by DNA ligase
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cloning vector experiment by Cohen
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cut fragments from two plasmids carrying antibiotic resistance genes with the same RE, followed by litigation with DNA ligase.
the strain exhibited trains from both plasmids. |
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when searching for a gene what is the contribution of the x-gal system?
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visual of blue/white colony growth.
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what is a shuttle-vector?
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plasmids that have multiple types of origins
expands the range of host cell types the plasmids can be inserted into. |
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what are phage vectors?
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mix viral DNA with fragment of interest.
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what are cosmids
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phage genomes that omit nearly all of the phage DNa, leaving more room for the fragment.
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transformation
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introductin of exracellular DNA directly into an organism.
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