Genetics CH.6

Which of the following statements about cotransduction is true? A) Nonlinked genes are passed simultaneously from one cell to another. B) A bacterial cell receives two adjacent genes on a single piece of DNA from the medium. C) Two bacterial cells within a culture are transformed by the same bacteriophage. D) The F factor plus a few chromosomal genes are passed from one cell to another.

B) A bacterial cell receives two adjacent genes on a single piece of DNA from the medium.

____________ is the transfer of genetic material between __________________ by direct cell-to-cell contact.

Conjugation; Bacteria

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

E) Genes are transferred from the donor to recipient in a linear fashion based upon time of contact.

Describe the origin of FF′ bacteria and merozygotes. The __________ element can enter the host bacterial chromosome, and upon returning to its independent state, it may _____________ a piece of a bacterial chromosome. When transferred to a bacterium with a _____________, a ___________, or merozygote, is formed.

F+ ; Pick up; Complete Chromosomes; Partial Diploid

________ 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.

F+; Merozygotes

T/F A bacterial strain that is pro + thi + leu − met − will grow on minimal media plus leucine and thiamine.

False

__________ is the process by which certain temperate phages can integrate their DNA into a bacterial chromosome.

Lysogeny

Identify the basis for chromosome mapping in the Hfr×F−Hfr×F− crosses.

The point of insertion and the direction of transfer are fixed. Breaking the conjugation tube at different times produces partial diploids with corresponding portions of the donor chromosome being transferred. The mapping of genes is based on time.

_____________ is virus-mediated DNADNA recombination.

Transduction

____________ (does not require cell-to-cell contact) is the process where foreign DNADNA enters recipient __________ and recombines with the host's chromosome

Transformation; Bacteria

The interrupted mating technique was used with a series of Hfr strains and the following results were obtained. 1) LQRYX 2) QLPZ 3) BTZP 4) LPZTB 5) PLQRY What is the order of the genes?

XYRQLPZTB

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

crossing-over (recombination)

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

log

Bacteriophages engage in two interactive cycles with bacteria. What are these cycles?

lytic and lysogenic

The clearing made by bacteriophages in a "lawn" of bacteria on an agar plate is called a ________.

plaque

The latent, integrated phage is called a ____________

prophage

Which of the following statements about conjugation is true? A) The F factor is an element that is found in the chromosome of an F+ cell. B) DNA is transferred from an F+ cell to an F− cell. C) One strand of DNA from an F+ cell integrates into the chromosome of an F- cell, and the other strand is degraded. D) Only competent cells can undergo conjugation.

B) DNA is transferred from an F+ cell to an F− cell.

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

B) donor F+ recipient F

Genetic recombination in ____________ takes place in three ways: conjugation, transformation, and transduction.

Bacteria

____________ can reproduce within the host cell of the infected ____________

Bacteriophages; Bacteria

All EXCEPT which of the following statements about bacteriophages are true? A) They use the metabolic machinery of a bacterial cell to produce more copies of themselves. B) They are viruses. C) Within their heads, they can pack the main chromosome from one cell and transfer it to another. D) They can pick up bacterial genes during the process of infecting a bacterial cell.

C) Within their heads, they can pack the main chromosome from one cell and transfer it to another

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 strain.

Hfr (wild type) × F (auxotroph)

A _________ results when bacteria in a "lawn" are infected by a phage, and its progeny destroy the bacteria.

Plaque

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

Prototrophs

How is a merozygote formed?

The F factor and several adjacent genes are excised from the chromosome of an F+ cell and transferred to an F− strain.

An episome is __________.

a plasmid that may exist separately or be integrated into the main bacterial chromosome

A bacteriophage that is capable of entering either a lytic or lysogenic cycle is called a(n) ________

temperate bacteriophage