Lab 10 Flashcards
(22 cards)
what is Streptomycin?
an antibiotic produced by soil bacteria of the genus Streptomyces and active against both gram-positive and gram-negative bacteria, including species resistant to other antibiotics was the first antibiotic remedy for tuberculosis.
what is Ampicillin?
a semisynthetic penicillin having a broader antibacterial spectrum of action than that of penicillin G. It is effective against gram-negative and gram-positive bacteria and used to treat gonorrhea and infections of the intestinal, urinary, and respiratory tracts
what are plasmids ?
Circular pieces of DNA that exist separately from chromosomal DNA
what is significant about plasmids?
Can contain gene of interest which can be inserted in bacteria.
-carry genes that mediate antibiotic resistance.
What if we have a gene we want to replicate?
we can let the bacteria reproduce itself with this plasmid within it, hence the plasmid will replicate as the bacteria replicates/multiplies during incubation.
What is ORI ?
where replication begins
what is promoter region?
where transcription begins
what are restriction sites?
where restriction enzymes cut to insert a gene of interest
What is the antibiotic-resistant gene?
Antibiotic resistance is plasma-mediated
-pick out bacterial cells that underwent transformation or those who up took the plasmid.
if bacteria has plasmid=it will grow on plate with the antibiotic the plasmid allows resistance for.
What is transformation?
The uptake of DNA by a cell from its environment.
Why do we do heat shock?
to open the cell walls for the plasmids to enter the bacteria
what is conjugation?
Transfer of DNA molecules between bacteria through direct contact using a pilus bridge.
-The F factor is what contains the genes to create the sex pillus
What is Basic conjugation?
F- cells become F+ after receiving the F factor.
which initiates basic conjugation and how?
F+ cells initiate conjugation (donor) By extending an F pilus toward the F- cell
What is the role of F- cells?
are the recipients
What is Hfr conjugation?
Hfr cells do not finish the process of conjugation however they still initiate conjugation; the F factor gene is the last piece of DNA that is transferred so it does not always make it to the recipient bacteria.
What is the last DNA factor in Hfr conjugation?
F- factor DNA
What is incompleteness due to?
-pilli fragility
-f- factor DNA not transferred
-cell remain as F-
-undergo high frequency recombination
Which part of the plasmid allows for the selection of these bacteria that contain our gene of interest?
antibiotic resistance
Do Hfr cells transfer the F factor?
no they do not
What happens if bacteria uptakes a bacteria for ampicillin resistance?
should grow on an agar plate made with ampicillin
If one bacteria can resist streptomycin and another can resist ampicillin, what happens if we mix the bacteria and grow them together
Conjugation will occur and the transfer of DNA happens