Deck 7: Genetic Transfer and Mapping in Bacteria and Bacteriophages

Question 1

The process of conjugation may introduce new alleles into the recipient strain, altering its genotype.

Answer 1

True

Question 2

Which mechanism of genetic transfer utilizes a sex pilus?

A) Transformation
B) Transduction
C) Conjugation
D) All of the answers are correct

Answer 2

C

Question 3

In conjugation the DNA that will be transferred from the donor cell to the recipient cell is

A) single-stranded.
B) double-stranded.
C) triple-stranded.
D) a mixture of single and double stranded.

Answer 3

A

Question 4

Which of the following mechanisms refer to when a bacteria assimilates genetic material (DNA) directly from the environment?

A) Transformation
B) Transduction
C) Conjugation
D) All of the answers are correct

Question 5

Which of the following mechanisms of genetic transfer was first observed by Lederberg and Tatum (1946) in Escherichia coli?

A) Transformation
B) Transduction
C) Conjugation
D) All of the answers are correct

Question 6

Which of the following is correct concerning F factors?

A) It may integrate into the host chromosome
B) It stands for fertility factor
C) It allows conjugation to occur
D) F+ bacteria act as donor strains in conjugation
E) All of the answers are correct

Question 7

During conjugation, one strand of the F factor DNA remains in the donor cell and one strand is transferred to the recipient cell.

Question 8

Interrupted mating is defined as ____________.

A) the inability of a bacteriophage to transfer genetic material
B) a mechanism of transformation
C) a process of asexual reproduction in bacteria
D) a process by which conjugation is stopped using a blender

Question 9

The protein complex that initiates the process of conjugation following contact between two bacteria is called the _________.

A) origin of transfer
B) T DNA
C) relaxosome
D) nucleoprotein

Question 10

The site on a plasmid that is digested, producing a single strand of DNA, to allow conjugation to occur is called the ____________.

A) origin of transfer
B) relaxase
C) nucleoprotein
D) T DNA

Question 11

First observed by Lederberg and Zinder (1952) in Salmonella typhimurium.

A) Transformation
B) Transduction
C) Conjugation
D) All of the answers are correct

Question 12

Which of the following represents a mechanism of genetic transfer in bacteria?

A) Transformation
B) Transduction
C) Conjugation
D) All of the answers are correct

Question 13

Which of the following mechanisms of genetic transfer utilizes a physical connection between two bacteria?

A) Transformation
B) Transduction
C) Conjugation
D) All of the answers are correct

Question 14

Which of the following is true regarding bacterial genetics?

A)Bacteria are usually diploid organisms
B)Bacteria primarily reproduce sexually
C)The patterns of inheritance in bacteria are studied using different mechanisms than eukaryotes
D)Bacteria generally have linear chromosomes

Question 15

Mechanism of genetic transfer that uses competent cells.

A) Transformation
B) Transduction
C) Conjugation
D) All of the answers are correct

Question 16

The enzyme that allows the reforming of a circular plasmid following conjugation is called _________.

A)relaxosome
B)relaxase
C)F' factor
D)nucleoprotein
E) pili protein

Question 17

Which of the following is true regarding conjugation?

A) The bacteria must be in physical contact
B) Most bacterial species have the ability to conjugate
C) Strains called donor strains can transfer genetic information
D) Donor strains can convert non-donor strains into donor strains
E) All of the answers are correct

Question 18

A histidine, methionine auxotroph _________.

A) can synthesize only histidine and methionine
B) can only use histidine and methionine as nutrition sources
C) cannot synthesize histidine and methionine
D) is killed by histidine and methionine
E) lacks proteins with histidine or methionine

Question 19

The process of interrupted mating may be used to do which of the following?

A) Inhibit transduction
B) Convert the recipient cell to F⁺
C) Determine the relative position of bacterial genes
D) Alter the genotype of the donor cell

Question 20

Which of the following uses a bacteriophage as an intermediary for the genetic information?

A) Transformation
B) Transduction
C) Conjugation
D) All of the answers are correct

Question 21

Which of the following conditions must be correct for transformation to occur?

A) Temperature
B) Ionic conditions
C) Correct nutrient balance
D) All of the answers are correct

Question 22

What is the order of the genes in the question?

A) abc
B) bac
C) acb

Question 23

Small circular pieces of DNA that are not associated with the bacterial chromosome are called _______.

A) heteroduplex
B) plasmids
C) relaxosome

Question 24

A cell with an F factor integrated into the bacterial chromosome is called __________.

A) Hfr
B) F+
C) Conjugative plasmid

Question 25

Which of the following matings would have the highest frequency of chromosomal gene transfer?

A) F⁺ x F^-
B) F' x F^-
C) Hfr x F^-

Question 26

The use of bacteriophages to map bacterial genes is called ___________.

A) generalized transduction
B) cotransduction
C) transformation
D) conjugation
E) none of the answers are correct

Question 27

Which of the following is inhibited by DNAse?

A) Transformation
B) Conjugation
C) Transduction
D) None of the answers are correct

Question 28

Cotransduction establishes the general order of genes on a bacterial chromosome, while conjugation is more specific and thus may be used to establish precise distances.

Question 29

A minute is the basic unit of map distance in bacteria.

Question 30

Loss of function mutations are easier to study in _______ organisms, such as bacteria.

A) haploid
B) diploid
C) triploid

Question 31

Competence factors do which of the following?

A) Allow the formation of a sex pilus
B) Promote bacteriophages binding for transduction
C) Allow DNA in the environment to bind to the cell surface
D) Inhibit genetic transfer between donor and recipient cells

Question 32

What is the equation that would be used to determine the distance between two genes with a cotransduction frequency of 0.68?

A) 0.68=(1 - d/2)³
B) d=.68³ - 1
C) d=(1-.68)²

Question 33

Which of the following is correct regarding a prophage?

A)It is used by virulent phages
B)It is used in the lytic cycle of viral replication
C)It does not directly enter into the cell being infected
D)It is copied along with the bacterial chromosome during replication

Question 34

Based on the following data, what two genes are farthest apart?

A) a-b
B) b-c
C) a-c

Question 35

What is the maximum size of the

A) 10%-20%
B) 30%
C) 0.5%-1%
D) 1%-2.5%
E)coli chromosome capable of being carried by a P1 phage?

Question 36

During conjugation, one gene (A) is found to transfer to the recipient bacteria 26 minutes following the start of conjugation, while a second gene (M) is found to transfer 37 minutes following the start of conjugation. A third gene (T) transfers 45 minutes following the start of conjugation. Based on this information, which of the following is true?

A) Genes A and M have a genetic distance of 11 minutes
B) Genes A and T have a genetic distance of 19 minutes
C) Genes M and t have a genetic distance of 8 minutes
D) The order of the genes is A M T
E) All of the answers are correct

Question 37

Who was the first to discover the process of natural transformation?

A) Morgan
B) Sturtevant
C) Griffith
D) Avery

Question 38

A phage that can carry a larger piece of a bacterial chromosome would have what type of effect on cotransduction frequencies?

A) Raise the cotransduction frequency
B) Lower the cotransduction frequency
C) Have no effect on the cotransduction frequency

Question 39

A structure called a(n) _______ allows the transfer of genetic information during conjugation.

A) F factor
B) plasmid
C) sex pilus
D) transformation bridge

Question 40

The units of genetic distance derived from bacterial conjugation studies are called _____.

A) seconds
B) map units
C) centimorgans
D) recombination units
E) minutes

Question 41

In a conjugation experiment not all of the cells receiving two genes will demonstrate an altered phenotype for both genes. What is the most likely explanation of this phenomenon?

A) One gene is toxic to the cell
B) Transferred genes must undergo recombination for genotypic conversion of the recipient cell and there is a possibility that only one gene will be recombined into the recipients chromosome
C) The transferred DNA is rapidly degraded by the recipient cell and one gene can be degraded before it is recombined into the host chromosome
D) It is not physically possible to recombine more than one gene into a single host genome per conjugation event

Question 42

An Hfr strain is produced when

A) an F episome integrates into the E. coli chormosome.
B) an F episome leaves the E. coli chromosome.
C) an F episome is transferred to a new cell.
D) an F episome leaves the host chromosome and removes some of the host chromosome.

Question 43

In the experiment performed by Benzer for intragenic mapping which of the following is the most critical control?

A) Perform the experiment with each different virus alone to determine the rate of reversion mutation
B) Re-type the strain of E. coli
C) Test the agar to make sure it can support E. coli and viral growth
D) Perform at least five dilutions to make sure the dilutions were performed correctly

Question 44

What is the correct order for the steps in transduction?

A) 1) Phage infects cell 2) Phage transported DNA recombines with chromosome of new cell 3) Host DNA digested into fragments 4) Some phage accidently carry host DNA fragment 5) Phage infects new cell
B) 1) Phage infects cell 2) Phage transported DNA recombines with chromosome of new cell 3) Host DNA digested into fragments 4) Phage infects new cell 5) Some phage accidently carry host DNA fragment
C) 1) Phage infects cell 2) Host DNA digested into fragments 3) Some phage accidently carry host DNA fragment 4) Phage infects new cell 5) Phage transported DNA recombines with chromosome of new cell
D) 1) Phage infects cell 2) Phage transported DNA recombines with chromosome of new cell 3) Some phage accidently carry host DNA fragment 4) Phage infects new cell 5) Host DNA digested into fragments

Question 45

Complementation experiments are used to determine if two observed mutations that are associated with the same trait are actually in the same gene.

Question 46

In the Lederberg and Tatum experiment what is the purpose of performing the experiment with the strains without adding them together?

A) It serves as a control to calculate the rate of reversion mutations
B) There is no experimental purpose to performing that part of the experiment
C) It tests that the strains were made correctly
D) It tests to make sure the media was made correctly

Question 47

Most biologists consider viruses to be living organisms, which are classified with the bacteria.

Question 48

Although there are several different types of plasmids they all

A) can confer some kind of selective growth advantage depending on environmental conditions.
B) can induce a mating phenotype.
C) result in horizontal transfer.
D) make cells resistant to antibiotics

Question 49

In an experiment with an Hfr cell if the uvrA gene is transferred 1 minute and the pyrB gene is transferred at 2.5 minutes then where is the oriT of the Hfr cell located? Use the map of the

A) 70 minutes
B) 90 minutes
C) 100 mintues
D) 97.5 minutes

Question 50

Acquired antibiotic resistance between two different species is an example of vertical gene transfer.

Question 51

What strategy did Benzer use to perform intragenic mapping?

A) Infection of a cell with two different viruses that had mutations in the same gene could not result in a wild type virus by recombination
B) Infection of a cell with two different viruses that had mutations in the same gene would result in a wild type virus by transduction
C) Infection of a cell with two different viruses that had mutations in different genes could result in a wild type virus by recombination
D) Infection of a cell with two different viruses that had mutations in the same gene could result in a wild type virus by recombination

Question 52

Which statement is true concerning intragenic and intergenic gene mapping?

A) The number of expected wild type recombinant viruses will be greater in intragenic mapping than with intergenic mapping
B) Intergenic gene mapping can only be performed in viruses.It is not performed in bacteria while intragenic mapping is performed in both viruses and bacteria
C) Intragenic mapping is the mapping of mutations within a gene while intergenic mapping is the mapping of genes with respect to each other
D) Intergenic mapping is the mapping of mutations within a gene while intragenic mapping is the mapping of genes with respect to each other

Question 53

The transfer of genetic material from two unrelated species is called ________.

A) Vertical gene transfer
B) Conjugation
C) Sexual reproduction
D) Binary fission
E) Horizontal gene transfer

Question 54

Competent cells are those used in studies of conjugation.

Question 55

In formation of plaques by bacteriophages which of the following statements is true?

A) A plaque is the result of several different viruses initially infecting a single cell
B) The plaque is the result of a single virus that has replicated in many bacterial cells in a localized area
C) A plaque results when a single virus infects one cell and then does not infect any other cell
D) Plaques are the areas where cells have not been infected at all

Question 56

In the experiment performed by Lederberg and Tatum bacteria of different genotypes had to be mixed together to obtain genetic transfer. However, Davis performed the experiment in a slightly different manner by separating cells with a filter incapable of allowing bacteria to pass. What possibility did the experiment by Davis exclude that could have occurred by the protocol used by Lederberg and Tatum?

A) transformation
B) conjugation
C) generalized transduction
D) specialized transduction

Question 57

The results below are from an interrupted conjugation experiment performed with an Hfr strain. Which genes could also be mapped with generalized transduction?

A) argR and argG only
B) All three could be mapped to each other using generalized transduction
C) argR could be mapped to recA and argG could be mapped to recA but argR and argG are too close to each other to be mapped using generalized transduction
D) Only argG could be mapped with recA since argR is farther away from recA there would be little recombination that would include all three genes together and so argR could not be reliably mapped using generalized transduction.

Question 58

An episome is a segment of bacterial DNA that can exist as a plasmid or be integrated into the bacterial chromosome.

Question 59

How can the complementation test discriminate between two viruses that have a mutation in the same gene versus two viruses that have mutations in the same gene?

A) If the viruses have mutations in the same gene then, depending on the assay, a significant number of plaques will be produced or a significant number of plaques will have a wildtype phenotype. If the mutations are in the different genes few, if any, wild type plaques will be seen..
B) If the viruses have mutations in different genes then, depending on the assay, a significant number of plaques will be produced or a significant number of plaques will have a wildtype phenotype. If the mutations are in the same gene few, if any, wild type plaques will be seen.
C) If the mutations are in the same gene the complementation test will result in recombinant viruses that are wildtype but if the mutations are in different genes no recombinant viruses will be produced.
D) If the mutations are in different genes the complementation test will result in recombinant viruses that are wildtype but if the mutations are in the same gene no recombinant viruses will be produced.