Old Exam 2 practice problems

Question 1

The transfer of a naked fragment of DNA between bacteria is called?

Answer 1

Transformation

Question 2

The transport of bacterial DNA to other bacteria via bacteriophages is called?

Answer 2

Transduction

Question 3

What happens during a F+ xF- mating?

Answer 3

DNA is transferred from F+ to F- cells

Question 4

Integrated (Hfr) - In this state the factor has integrated into the bacterial chromosome via a recombination. T or F?

Answer 4

True

Question 5

The transfer of genetic information is in what direction?

Answer 5

Unidirectional and partial

Question 6

What is a strain of bacteria that harbors a prophage is called?

Answer 6

Lysogen

Question 7

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.

Answer 7

False : It occurs in specialized transduction

Question 8

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+?

Answer 8

Sexduction

Question 9

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.

Answer 9

False

Question 10

________ is the recombination of DNA sequences having nearly the same nucleotide sequence and involving Rec A proteins

Answer 10

Homologous recombination

Question 11

F factor plasmids play a major role in what bacterial process?

Answer 11

Conjugation

Question 12

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.

Answer 12

True

Question 13

Usage of a virus vector to deliver the DNA into the target cell is what?

Answer 13

Transduction

Question 14

This type of recombination does not require homologous sequences and is important for the integration of viral genomes into bacterial chromosomes are?

Answer 14

Site-specific recombination

Question 15

Horizontal transfer can best be described as what?

Answer 15

The transmission of genetic information from one independent, mature organism to another.

Question 16

The name of the process in which plasmids can be eliminated form a cells is called what?

Answer 16

Curing

Question 17

The type of plasmid makes the host more pathogenic?

Answer 17

Virulence plasmid

Question 18

What type of plasmid carries genes encoding enzymes that degrade substances such as aromatic compounds, pesticides, or sugar?

Answer 18

Metabolic Plasmid

Question 19

Mobile genetic elements that carry the genes required for integration into host chromosomes are?

Answer 19

Transposons

Question 20

Composite transposons are formed when?

Answer 20

Two IS elements integrate into a chromosome with only a small distance between separating them

Question 21

In which type of transduction does the transducing particle carry only specific portions of the bacterial genome?

Answer 21

Specialized transduction

Question 22

The tranposase gene encodes an enzyme that:

Answer 22

Facilitates site-specific integration of transposable elements

Question 23

What are the three tools by microbial genetisists?

Answer 23

plasmids, bacteriophage, transposable elements

Question 24

__________ promote the resolution of the cointegrates by recognizing the res sequences.

Answer 24

Resolvases

Question 25

________ promote specific recombination by recognizing two sites that are in reverse orientation to each other.

Answer 25

DNA invertases

Question 26

True or False: The ColE1-derived plasmid replication is regulated by a ctRNA and protein.

Answer 26

False

Question 27

True or False: In the plasmids the oriV determine the mechanism of replication, host range, and regulate the number of copy.

Answer 27

True

Question 28

True or False: The oriV region of ColE1-derived plasmid contains several repeats of a certain set of DNA bases (iteron sequences)

Answer 28

True

Question 29

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.

Answer 29

True

Question 30

An integrin with a large number of cassettes, what is it?

Answer 30

super-integron

Question 31

What are mutations in the Lac Operon that seem to abolish expression called?

Answer 31

non-inducible

Question 32

LacO mutations are cis dominant. True or False?

Answer 32

True

Question 33

What are the three loci responsible for lactose metabolism?

Answer 33

LacZ, Lac Y, LacA

Question 34

Bacteriophages need a host cell to reproduce. Name the two life cycles which phages can undergo and explain what the difference is for them.

Answer 34

Lytic and Lysogenic cycle

Question 35

When a transposon moves within a host cell it?

Answer 35

Sometimes leaves a copy of itself from the original location

Question 36

Type of site-specific recombinase that breaks and rejoins DNA in res sequences?

Answer 36

resolvase

Question 37

What are the two classes of phage transduction

Answer 37

generalized and specialized transduction

Question 38

In the absence of tryptophan, the trp repressor is?

Answer 38

Inactive and cannot bind to the operator

Question 39

The regulation performed by regulatory genes; each step triggers the next and stops the preceding what?

Answer 39

Regulatory cascade

Question 40

Single regulatory protein that controls a large number of operons.

Answer 40

Regulon

Question 41

How many classes of CAP (catabolite activator protein) are there

Answer 41

Three; Class I, II, and III

Question 42

The mRNA strand is coded by the what?

Answer 42

Anti-sense strand (3'-5')

Question 43

How many classes of transposons are the there?

Answer 43

2; Class I and Class II