Nester's Microbiology: A Human Perspective

Denise Anderson, Sarah Salm, Deborah Allen

Chapter 8

Bacterial Genetics - all with Video Answers

Educators

Chapter Questions

Problem 1

A culture of $E$. coli is irradiated with ultraviolet (UV) light. Answer questions 1 and 2 based on this statement. The UV light specifically
a) joins the two strands of DNA together by covalent bonds.
b) joins the two strands of DNA together by hydrogen bonds.
c) forms covalent bonds between thymine molecules on the same strand of DNA.
d) forms covalent bonds between guanine and cytosine.
e) deletes bases.

Sylvia Puglisi

Sylvia Puglisi

Numerade Educator

Problem 2

The highest frequency of mutations would be obtained if, after irradiation, the cells were immediately
a) placed in the dark.
b) exposed to visible light.
c) shaken vigorously.
d) incubated at a temperature below their optimum for growth.
e) The frequency would be the same no matter what the environmental conditions are after irradiation.

Sylvia Puglisi

Numerade Educator

Problem 3

Penicillin enrichment of mutants works on the principle that
a) only Gram-positive cells are killed.
b) cells are most sensitive to antimicrobial medications during the lag phase of growth.
c) most Gram-negative cells are resistant to penicillin.
d) penicillin kills only growing cells.
e) penicillin inhibits formation of the lipopolysaccharide layer.

Sylvia Puglisi

Numerade Educator

Problem 4

Repair mechanisms that occur during DNA replication are
1. mismatch repair.
2. proofreading by DNA polymerase.
3. light repair.
4. SOS repair.
5. excision repair.
a) 1,2
b) 2,3
c) 3,4
d) 4,5
e) 1,5

Sylvia Puglisi

Numerade Educator

Problem 5

You are trying to isolate a mutant of wild-type $E$, coli that requires histidine for growth. This can best be done using
1. direct selection.
2. replica plating.
3. penicillin enrichment.
4. a procedure for isolating conditional mutants.
5. reversion.
a) 1,2
b) 2,3
c) 3,4
d) 4,5
e) 1,5

Sylvia Puglisi

Numerade Educator

Problem 6

The properties that all plasmids share are that they
1. all carry genes for antimicrobial resistance.
2. are self-transmissible to other bacteria.
3. always occur in multiple copies in the cells.
4. code for non-essential functions.
5. replicate in the cells in which they are found.
a) 1,2
b) 2,3
c) 3,4
d) 4,5
e) 1,5

Sylvia Puglisi

Numerade Educator

Problem 7

The addition of DNase to a mixture of donor and recipient cells will prevent gene transfer via
a) DNA transformation.
b) chromosome transfer by conjugation.
c) plasmid transfer by conjugation.
d) generalized transduction.

Sylvia Puglisi

Numerade Educator

Problem 8

An Fpilus is essential for
1. DNA-mediated transformation.
2. chromosome transfer by conjugation.
3. plasmid transfer by conjugation.
4. generalized transduction.
5. cell movement.
a) 1,2
b) 2,3
c) 3,4
d) 4,5
e) 1,5

Sylvia Puglisi

Numerade Educator

Problem 9

A plasmid that can replicate in $E$. coli and $P$ seudomonas is most likely a/an
a) broad host range plasmid.
b) self-transmissible plasmid.
c) high-copy-number plasmid.
d) essential plasmid
e) low-copy-number plasmid.

Sylvia Puglisi

Numerade Educator

Problem 10

The frequency of transfer of an $\mathrm{F}^{\prime}$ molecule by conjugation is closest to the frequency of transfer of
a) chromosomal genes by conjugation.
b) an $\mathrm{F}$ plasmid by conjugation.
c) an $F$ plasmid by transformation.
d) an $F$ plasmid by transduction.
e) an $\mathrm{R}$ plasmid by DNA transformation.

Sylvia Puglisi

Numerade Educator