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46 Cards in this Set
- Front
- Back
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What will happen on a nutrient agar if there is starch?
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amylase is induced
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What will happen on a nutrient agar if there is starch and glucose?
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the amalyse is not induced until the glucose is used up: glucose shuts off the operon
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What does amylase do
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break down starch to glucose
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What do you do to the plate to test for amylase
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flood plate with iodine
it will stick to starch and make it purple If it is clear, then the area has no starch because it was degraded by amylase |
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What was the bacteria used for the amylase test?
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bacillus cereus
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Which plate should have clear zones: starch plate or starch-glucose plate?
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starch plate
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What are 2 methods to prepare cells for transformation?
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cold and heat shock bacteria in CaCl2 solution
electroporation |
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What do you do to each tube in the transformation experiment
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put CaCl2 on ice and inoculate 10 microliters of E.Coli into the positive tube
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What is the only tube in which transformation can occur?
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positive
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What does heat shock do
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allows transformation to occur
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How is the pBLU plasmid introduced into E. coli cells?
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by transformation
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What makes up pBLU plasmid?
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beta galactosidase gene
AmpR gene (beta lactamase gene) |
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What does beta galactosidase do?
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cleaves lactose to glucose and galactose
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What does beta lactamase do?
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breaks beta lactam ring and destroys ampicillin
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What will happen to the E. Coli cells after transformation with pBLU plasmid?
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they will become resistant to amplicillin and can grow on medium supplemented with ampicillin
Also, they can produce beta-galactosidase which can cleave X-gal, a lactose analog, present in substrate and produce blue colonies |
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What is a lactose analog
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X-gal
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Will every cell get the pBLU plasmid
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no
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What will grow on the LB amp plate?
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positive (ones that received the plasmid) and mutations
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What will happen on the LB amp + Xgal plate?
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ones with the pBLU plasmid should grow, and drug resistant mutants will grow
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What will happen if colonies on the LB amp Xgal plate turn blue?
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truly transformed
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What does it mean if there is white on the LB amp Xgal plate?
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that is a drug resistant mutant gene
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What is the experiment used to demonstrate that the enzyme can be induced by the presence of starch and suppressed by presence of glucose?
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enzyme induction
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How do you detect the presence or absence of starch in a plate
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flood with iodine
clear zones- no starch purple- starch |
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What is the enzyme that degrades starch?
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amylase
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What are competent cells?
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ones that can undergo transformation and receive the plasmid
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What method did we use in the transformation lab?
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cold and heat shock in CaCl2 solution
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What are the 2 marker genes on the pBLU plasmid?
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beta-galactosidase and ampR
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Why do transformed cells become resistant to ampicillin and gain ability to produce beta galactosidase
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because they acquire the plasmid which includes the DNA
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What is it called when the cells convert their newly modified genotype into a functionally ampicillin resistant phenotype?
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recovery period
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What is the reason to use ampicillin in the agar plate to detect transformed cells?
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because the transformed cells will be ampicillin resistant and can still grow
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What does beta galactosidase do?
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breaks down lactose into glucose and galactose
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How can you detect which mos make beta galactosidase on the Xgal plate?
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blue colony
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What is a cell that is able to take up DNA from its environment?
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competent cell
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What are small circular pieces of extrachromosomal DNA?
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plasmids
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What is cells being suspended in a DNA solution and sujected to high voltage electric impulses that destrabilize the cell membrane resulting in increased permeability and enabling DNA to pass into cells?
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electroporation
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What is a method of horizontal passage of genetic material from one bacterial cell to another by means of a bacteriophage?
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transduction
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What occurs when bacterial DNA is transfered from one cell to another via the formation of a protoplasmic bridge called a sex pilus?
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conjugation
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What has heavy growth at 20 degrees C?
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all but Bacillus stearothermophilus
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What has heavy growth at 37 degrees C
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pseudomonas fluorescens
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What has growth at the top of thioglycollate broth?
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all but E coli
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What has growth in the middle of thioglycollate broth?
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E coli and streptococcus lactis
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What has growht at the bottom of thioglycollate broth?
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everything but micrococcus luteus
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HOw can micrococcus luteus grow?
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aerobic, candle jar
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How can E coli grow?
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heavily in aerobic, biobag, and heavy in candle jar
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How can Streptococcus lactis grow?
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heavy in all 3
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How can clostridium perfringens grow?
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biobag only
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