chapter 6 homework

Question 1

what type of bacterial cell is partially diploid?

Answer 1

F’ exconjugant

Question 2

what DNA sequence acts as a site of integration for a prophage?

Answer 2

att site

Question 3

______________ are DNA sequences that serve as the site of recombination between the F plasmid and the bacterial chromosome

Answer 3

IS elements

Question 4

during transduction, when would you expect to observe fragmentation of the host chromosome?

Answer 4

when the phage chromosomes are packaged into phage heads

Question 5

all of the following are characteristics of insertion sequences except:
- they encode protein
- they are flanked by inverted repeats
- there can be more than one copy of an IS element in a bacterial genome
- a copy of the insertion sequence becomes integrated at a new location

Answer 5

a copy of the insertion sequence becomes integrated at a new location

Question 6

the role of transpose activity in IS element transposition includes
- regulating expression of the target sequence
- truncating other proteins
- cutting DNA at the target sequence
- filling in single-stranded gaps after IS insertion

Answer 6

cutting DNA at the target sequence

Question 7

which of the following transposition events is most likely to result in a loss of function mutation?
- insertion near promoter region of gene
- transposition of IS that contains stop codon within inverted repeat sequence
- insertion of IS element within coding region of a gene

Answer 7

insertion of IS element within coding region of a gene

Question 8

what results would be expected from a plaque assay if the dilution factor of the phage-infected culture were too low?

Answer 8

the entire lawn of bacteria would be lysed

Question 9

in Hfr transfer, what happens to linear DNA that does not recombine with the host chromosome?

Answer 9

degradation

Question 10

when F+ conjugation occurs successfully, only one copy of the F plasmid single-stranded DNA is transferred. what else must minimally occur?

Answer 10

stopping the rolling circle replication after one copy length, circularization, and replication

Question 11

which process of genetic exchange in bacteria is capable of transferring only a small, specific region of the bacterial chromosome?

Answer 11

specialized transduction

Question 12

true or false: lateral gene transfer increases the efficiency of antibiotics against normally sensitive strains

Answer 12

false

Question 13

which mechanism of gene transfer is capable of transferring the largest chromosome segment from donor to recipient?

Answer 13

conjugation

Question 14

which mechanism of gene transfer is capable of transferring the smallest chromosome segment from donor to recipient?

Answer 14

transduction

Question 15

which are donor cells?

Answer 15

F+, Hfr, F-

Question 16

which are recipient cells?

Answer 16

F-

Question 17

which cells can convert exconjugants to a donor state?

Answer 17

F’, F+

Question 18

which cells can transfer a donor gene to exconjugants?

Answer 18

Hfr, F’

Question 19

which cell is a donor cell that will not change the genotype of the recipient cell other than make it a donor cell

Answer 19

F+

Question 20

which cell is a donor cell that will change the genotype of the recipient cell in addition to making it a donor cell?

Answer 20

F’

Question 21

which cell is a donor cell that will change the genotype of the recipient cell but will not make it a donor cell?

Answer 21

Hfr