Old Exam 2 practice problems Flashcards
The transfer of a naked fragment of DNA between bacteria is called?
Transformation
The transport of bacterial DNA to other bacteria via bacteriophages is called?
Transduction
What happens during a F+ xF- mating?
DNA is transferred from F+ to F- cells
Integrated (Hfr) - In this state the factor has integrated into the bacterial chromosome via a recombination. T or F?
True
The transfer of genetic information is in what direction?
Unidirectional and partial
What is a strain of bacteria that harbors a prophage is called?
Lysogen
T or F. In general transduction a lysogenic phage undergoes recombination with the host genome and later when an independent phage genome, and it carries one or more host genes with it.
False : It occurs in specialized transduction
An E. coli strain is F- lac Z- met+ bio+. Cells from this strain are mixed with an E. coli strain that is lac Z+ met- bio- and carrying an F’ episome with the
plac O+ lac Z+ DNA sequence on the episome, and cultured for several hours. Then cells were removed, washed, and transferred to minimal media containing lactose as the only sugar source. A few cells were able to grow on minimal media with lactose, and formed colonies. How did these few cells become lac Z+ met+ bio+?
Sexduction
True and False. In the cut-and-paste transposition cointegrate intermediate is formed, both strands of the DNA transpose and transposon leaves the donor DNA.
False
________ is the recombination of DNA sequences having nearly the same nucleotide sequence and involving Rec A proteins
Homologous recombination
F factor plasmids play a major role in what bacterial process?
Conjugation
True or False. An Hfr ( high frequencey of recombination) strain occurs when the F+ factor becomes integrated into the E. coli host chromosome, due to the presence of the insertion sequences.
True
Usage of a virus vector to deliver the DNA into the target cell is what?
Transduction
This type of recombination does not require homologous sequences and is important for the integration of viral genomes into bacterial chromosomes are?
Site-specific recombination
Horizontal transfer can best be described as what?
The transmission of genetic information from one independent, mature organism to another.
The name of the process in which plasmids can be eliminated form a cells is called what?
Curing
The type of plasmid makes the host more pathogenic?
Virulence plasmid
What type of plasmid carries genes encoding enzymes that degrade substances such as aromatic compounds, pesticides, or sugar?
Metabolic Plasmid
Mobile genetic elements that carry the genes required for integration into host chromosomes are?
Transposons
Composite transposons are formed when?
Two IS elements integrate into a chromosome with only a small distance between separating them
In which type of transduction does the transducing particle carry only specific portions of the bacterial genome?
Specialized transduction
The tranposase gene encodes an enzyme that:
Facilitates site-specific integration of transposable elements
What are the three tools by microbial genetisists?
plasmids, bacteriophage, transposable elements
__________ promote the resolution of the cointegrates by recognizing the res sequences.
Resolvases
________ promote specific recombination by recognizing two sites that are in reverse orientation to each other.
DNA invertases
True or False: The ColE1-derived plasmid replication is regulated by a ctRNA and protein.
False
True or False: In the plasmids the oriV determine the mechanism of replication, host range, and regulate the number of copy.
True
True or False: The oriV region of ColE1-derived plasmid contains several repeats of a certain set of DNA bases (iteron sequences)
True
True or False: In R1 and ColB1-P9 plasmids the number of copies is regulated by the amount of Rep protein using antisense RNA to inhibit the synthesis of Rep protein.
True
An integrin with a large number of cassettes, what is it?
super-integron
What are mutations in the Lac Operon that seem to abolish expression called?
non-inducible
LacO mutations are cis dominant. True or False?
True
What are the three loci responsible for lactose metabolism?
LacZ, Lac Y, LacA
Bacteriophages need a host cell to reproduce. Name the two life cycles which phages can undergo and explain what the difference is for them.
Lytic and Lysogenic cycle
When a transposon moves within a host cell it?
Sometimes leaves a copy of itself from the original location
Type of site-specific recombinase that breaks and rejoins DNA in res sequences?
resolvase
What are the two classes of phage transduction
generalized and specialized transduction
In the absence of tryptophan, the trp repressor is?
Inactive and cannot bind to the operator
The regulation performed by regulatory genes; each step triggers the next and stops the preceding what?
Regulatory cascade
Single regulatory protein that controls a large number of operons.
Regulon
How many classes of CAP (catabolite activator protein) are there
Three; Class I, II, and III
The mRNA strand is coded by the what?
Anti-sense strand (3’-5’)
How many classes of transposons are the there?
2; Class I and Class II
