Question 1

What is the adaptation hypothesis?
A)The bacteria will mutate so it can become an auxotroph.
B)The phage mutates to infect bacteria more effectively.
C)The phage mutates so it can't infect bacteria any longer.
D)The phage and bacteria both mutate so the phage becomes less virulent.
E)The phage stimulates the bacteria to mutate to become immune to the phage.

Accepted Answer

The adaptation hypothesis suggests that the presence of a phage stimulates the bacteria to mutate, allowing them to become immune to the phage.

Question 2

Which of the following is true about the interrupted mating technique?
A)The recipient bacterium will choose the best genes.
B)Time of contact is not applicable to this protocol.
C)Genes are transferred from the donor to recipient in a linear fashion based upon time of contact.
D)Donor will pass only beneficial genes to the recipient.
E)Genes will be passed from the centromere.

Accepted Answer

The interrupted mating technique involves interrupting the conjugation process between a donor and recipient bacterium at different time points and then observing which genes have been transferred. Genes are transferred in a linear fashion based upon the time of contact, with genes closer to the origin of transfer being transferred earlier. Therefore, choice C is the correct option. The other choices are incorrect because the recipient bacterium does not actively choose the genes, time of contact is important, the donor may transfer both beneficial and harmful genes, and genes are not passed from the centromere in bacteria.

Question 3

Assume that the gene trpA in an auxotrophic strain of E.coli is located at 27 minutes,whereas the gene pyrE is located at 81 minutes. Present an experimental scheme that would allow you to convert one of the auxotrophic strains to a prototrophic A)F⁺auxotroph × F^-wild type B)Hfr auxotroph × F^-wild type C)F⁺wild type × F^-auxotroph D)Hfr wild type × F^-auxotroph E)Hfr auxotroph × F^-auxotroph

Accepted Answer

The correct experimental scheme involves using a high frequency of recombination (Hfr) wild type strain of E. coli to mate with the auxotrophic strain. This allows for the transfer of genetic material from the wild type to the auxotroph, potentially providing the auxotroph with the necessary genes to revert to prototrophy.

Question 4

______can initiate chromosome transfer from one E.coli to another. A)An F⁺cell B)An F^-cell C)An Hfr cell D)A plasmid E)A temperate phage

Accepted Answer

Hfr cells have the ability to transfer portions of their chromosome to other bacterial cells during conjugation.

Question 5

What is a form of recombination in bacteria that involves the F plasmid?
A)fluctuation
B)transformation
C)conjugation
D)adaptation
E)transduction

Accepted Answer

Conjugation is a form of recombination in bacteria where genetic material is transferred through direct cell-to-cell contact. The F plasmid is commonly involved in conjugation, where a cell with an F plasmid (F+) transfers a copy of the plasmid to a recipient cell (F-). This results in the recipient cell becoming an F+ cell and gaining the ability to transfer genetic material to other cells.

Question 6

Jacob,Wollman,and others developed a linkage map of E.coli that is based on time.What form of recombination is involved in generating a linkage map based on time?
A)transduction
B)adaptation
C)time of transfer
D)conjugation
E)transformation

Accepted Answer

Conjugation involves the transfer of genetic material between bacterial cells through direct physical contact. Therefore, a linkage map based on time is likely generated through the observation of the transfer of genetic material over time via conjugation between E. coli cells.

Question 7

Max Delbrück presented the first evidence that bacteria are capable of spontaneous mutation.What is the name of the test that Delbrück used to demonstrate this phenomenon?
A)auxotrophic test
B)lag test
C)fluctuation test
D)prototrophic test
E)logarithmic test

Accepted Answer

Max Delbrück used the fluctuation test to demonstrate that bacteria are capable of spontaneous mutation. In this test, individual bacterial cultures are grown from single cells and then plated under conditions where only mutants can grow. The number of mutant colonies that grow is used to calculate the mutation rate. By seeing fluctuation in the number of mutations among the cultures, Delbrück showed that mutations were occurring spontaneously rather than being induced by external factors.

Question 8

What is an R plasmid?
A)They carry a gene for resistance to an environmental attribute,such as heavy metals,and genes for the transfer of the plasmid.
B)They function in bacterial recombination.
C)They are a plasmid that can exist in the chromosome or outside the chromosome.
D)They are the plasmids that carry the F factor.
E)It is an F factor that has picked up part of a bacterial genome.

Accepted Answer

R plasmids carry genes for resistance to certain environmental attributes, such as heavy metals, as well as genes for the transfer of the plasmid. These plasmids are commonly found in bacteria and contribute to the spread of antibiotic resistance.

Question 9

Once an exogenous foreign piece of DNA is in the bacterial cell,it is incorporated into the bacterial genome through ______.
A)transformation
B)conjugation
C)DNA replication
D)transduction
E)crossing- over recombination

Accepted Answer

The answer of Once an exogenous foreign piece of DNA...

Question 10

Name the general category into which double- stranded circular extrachromosomal DNA elements such as F factors,ColE1,and R would fall.
A)r- determinant
B)plaque
C)partial diploid
D)capsid
E)plasmid

Accepted Answer

Double-stranded circular extrachromosomal DNA elements such as F factors, ColE1, and R are plasmids, which fall into the general category of plasmids.

Question 11

Analyze the following growth of a bacterial colony. What is the genotype of the bacterium? A)bio⁺,leu⁺,lac^- B)bio⁺,thr⁺,leu⁺,met⁺ C)leu⁺,met⁺,lac⁺ D)leu⁺,met⁺,lac^- E)bio⁺,thr⁺,lac^-

Accepted Answer

The growth of a bacterial colony cannot determine the genotype of the bacterium. Therefore, it is not possible to identify the genotype based on the given information.

Question 12

______are bacteria that can grow on minimal medium and are assumed to be wild type. A)Prototrophs B)F⁺cells C)Auxotrophs D)Mutants E)Hfr

Accepted Answer

Prototrophs are bacteria that can grow on minimal medium, and are assumed to be wild type, meaning they have not undergone any mutations. Therefore, option A is the best choice.

Question 13

Which of the following is true about a merozygote? A)It can spontaneously form from an Hfr cell. B)Merozygotes were crucial to our understanding of the formation of the sex pilus. C)A merozygote can form if an F factor carries chromosomal DNA and is injected into an F^-cell. D)A conjugation with an Hfr donor will never produce a merozygote. E)It is formed from an Hfr to F⁺cross.

Accepted Answer

A merozygote can form if an F factor carries chromosomal DNA and is injected into a recipient cell. The recipient cell can then temporarily become diploid for the specific region of chromosomal DNA. The other choices are incorrect because: A) A merozygote cannot spontaneously form from an Hfr cell. B) Merozygotes may have played a role in understanding the sex pilus, but this does not make the statement true. D) Conjugation with an Hfr donor cell can produce a merozygote, depending on the circumstances. E) This answer choice is unclear and does not provide sufficient information to determine its accuracy.

Question 14

In which phase of the bacterial cell cycle do the cells grow most quickly?
A)stationary
B)fluctuation
C)log
D)adaptation
E)lag

Accepted Answer

During the log phase, bacteria are actively growing and dividing. This is the phase where cells are reproducing most rapidly, as they are in the ideal environment for growth and have not yet reached their maximum population density.

Question 15

______bacteria contain an F factor or plasmid that is capable of initiating conjugation.______bacteria contain an F plasmid that possesses a portion of the bacterial chromosome. A)F⁺; Merozygotes B)F^-; F⁺ C)F⁺; Hfr D)Merozygotes; F^- E)F^-; Hfr

Accepted Answer

F⁺ bacteria contain an F factor or plasmid that is capable of initiating conjugation. Merozygotes are formed when an F⁺ cell conjugates with an F^- cell and transfers a portion of its chromosome to the F^- cell.

Question 16

In a bacterial cross in which the donor Hfr is a⁺b⁺and the recipient strain F^- is a^-b^-,it is expected that recombinant bacteria______ . A)will be a mixture of a⁺b⁺,a^-b^-,and a^-b⁺ B)will all remain a^-b^- C)will all be a⁺b⁺ D)will be a mixture of a⁺b⁺,a^-b^-,a⁺b^-,and a^-b⁺ E)will be a mixture of a⁺b⁺and a^-b^-

Accepted Answer

The answer of In a bacterial cross in which the...

Question 17

______can exist integrated into the bacterial chromosome or as an autonomous plasmid unit in the cytosol.
A)Col plasmid
B)Temperate phages
C)Episomes
D)F' plasmid
E)R factor

Accepted Answer

Episomes can exist either integrated into the bacterial chromosome or as a autonomous plasmid unit in the cytosol. The other options do not have this flexibility. Col plasmids only exist as autonomous plasmids, temperate phages can integrate into the bacterial chromosome but cannot exist as an autonomous plasmid unit, F' plasmids are always integrated into the bacterial chromosome, and R factors are always autonomous plasmids.

Question 18

How do different strains of E.coli can reveal different linkage arrangements of genes in Hfr crosses?
A)They do not.All Hfr strains are identical.
B)Different strains may have different F factors and therefore different initiation points for chromosome transfer.
C)Hfr strains will demonstrate different areas of recombination,due to dominance and recessiveness of genes.
D)In different Hfr strains,different genes will be transferred based on where the centromere resides.
E)In different Hfr strains,genes can be in different order on the chromosome.

Accepted Answer

Different strains of E.coli can have different F factors integrated at various points in the chromosome, leading to different initiation points for chromosome transfer during Hfr conjugation. This results in different linkage arrangements of genes being revealed.

Question 19

______have lost,through ______,the ability to grow on minimal medium.
A)prototrophs; adaptation
B)mutants; adaptation
C)prototrophs; mutation
D)auxotrophs; mutation
E)auxotrophs; adaptation

Accepted Answer

Auxotrophs have lost the ability to grow on minimal medium due to a mutation which has disrupted their ability to synthesize a nutrient required for growth. Prototrophs, on the other hand, are able to grow on minimal medium as they can synthesize all the nutrients they need. Mutants and adaptation are general terms that may or may not be related to the loss of ability to grow on minimal medium. Therefore, option D best explains the situation.

Question 20

Describing bacterial conjugation,which of the following matings is most likely to result in a change from F^-to F⁺? A)donor F^-recipient Hfr B)donor Hfr recipient F⁺ C)donor Hfr recipient F^- D)donor F⁺recipient F^- E)donor F^-recipient F⁺

Accepted Answer

In bacterial conjugation, an F+ donor transfers the F plasmid to an F- recipient, converting it to F+.

Quiz 6: Genetic Analysis and Mapping in Bacteria and Bacteriophages

What is the adaptation hypothesis?

Which of the following is true about the interrupted mating technique?

Assume that the gene trpA in an auxotrophic strain of E.coli is located at 27 minutes,whereas the gene pyrE is located at 81 minutes. Present an experimental scheme that would allow you to convert one of the auxotrophic strains to a prototrophic

______can initiate chromosome transfer from one E.coli to another.

What is a form of recombination in bacteria that involves the F plasmid?

Jacob,Wollman,and others developed a linkage map of E.coli that is based on time.What form of recombination is involved in generating a linkage map based on time?

Max Delbrück presented the first evidence that bacteria are capable of spontaneous mutation.What is the name of the test that Delbrück used to demonstrate this phenomenon?

What is an R plasmid?

Once an exogenous foreign piece of DNA is in the bacterial cell,it is incorporated into the bacterial genome through ______.

Name the general category into which double- stranded circular extrachromosomal DNA elements such as F factors,ColE1,and R would fall.

Analyze the following growth of a bacterial colony. What is the genotype of the bacterium?

______are bacteria that can grow on minimal medium and are assumed to be wild type.

Which of the following is true about a merozygote?

In which phase of the bacterial cell cycle do the cells grow most quickly?

bacteria contain an F factor or plasmid that is capable of initiating conjugation.bacteria contain an F plasmid that possesses a portion of the bacterial chromosome.

In a bacterial cross in which the donor Hfr is a⁺b⁺and the recipient strain F^- is a^-b^-,it is expected that recombinant bacteria______ .

______can exist integrated into the bacterial chromosome or as an autonomous plasmid unit in the cytosol.

How do different strains of E.coli can reveal different linkage arrangements of genes in Hfr crosses?

have lost,through ,the ability to grow on minimal medium.

Describing bacterial conjugation,which of the following matings is most likely to result in a change from F^-to F⁺?