CHAPTER 17—BACTERIAL AND VIRAL GENETICS
MULTIPLE CHOICE
1. Escherichia coli is used in scientific investigations because it:
a.
grows quickly in huge numbers in nutrient solutions that are easy to prepare.
b.
is affected by bacteriophages.
c.
can be used in genetic studies.
d.
allows researchers to detect events that occur once within millions of offspring.
e.
all of these
2. Escherichia coli biochemical studies have added immeasurably to:
a.
the definition of genes.
b.
the definition of gene activities.
c.
the identification of biochemical pathways.
d.
all of these
e.
none of these
3. Neurospora and Aspergillus
a.
are bacteria.
b.
are used in a similar manner as E. coli to elucidate biochemical pathways.
c.
are prokaryotes.
d.
can be grown and analyzed biochemically as individual cells
e.
are affected by bacteriophages.
4. Eukaryotes that can be used in molecular studies include:
a.
Arabidopsis
b.
Saccharomyces
c.
Drosophila
d.
Neurospora
e.
all of these
5. Bacterial genes can be transferred from one bacterium to another by different mechanisms. The newly
introduced DNA can:
a.
recombine with DNA already present.
b.
generate genetic variability.
c.
exchange alleles between homologous regions from two different individuals.
d.
allow growth on minimal media
e.
all of these
6. As early as the 1940s, researchers knew that bacteria could be grown in a minimal medium. In this
minimal medium the most common source of organic carbon is:
a.
peptidase.
b.
glucose.
c.
rubisco.
d.
catalase.
e.
ammonium chloride.
7. Ammonium chloride is a commonly used salt in minimal media. The reason ammonium chloride is
used is because:
a.
it is an organic source of carbon.
b.
it provides nitrogen.
c.
it jellifies the media.
d.
it liquefies the media.
e.
it sterilizes the media.
8. Bacterial cultures with a large number of genetically identical cells are called:
a.
clone cultures.
b.
equal cultures.
c.
simple cultures.
d.
identical cultures.
e.
fresh cultures.
9. Auxotroph bacteria
a.
are mutant bacteria
b.
can grow on minimal media
c.
feed on proteins
d.
make their own nutrients
e.
make antibiotics
Use the figure above for the following question(s).
10. bio refers to a gene that governs a cell’s ability to synthesize biotin from inorganic precursors. The
designation bio+ indicates:
a.
that the allele is normal.
b.
that the allele is the mutant allele.
c.
that the bacterium is biologically active.
d.
that the bacterium is biologically inactive.
e.
that the bacterium cannot make its own biotin.
11. met refers to a gene that governs a cells ability to synthesize methionine from inorganic precursors.
The designation met- indicates:
a.
that the allele is normal.
b.
that the allele is the mutant allele.
c.
that the bacterium is biologically active.
d.
that the bacterium is biologically inactive.
e.
that the bacterium can make its own methionine.
12. leu refers to a gene that governs a cell’s ability to synthesize leucine from inorganic precursors. The
designation leu- indicates:
a.
that the allele is normal.
b.
that the allele is the mutant allele.
c.
that the bacterium is biologically active.
d.
that the bacterium is biologically inactive.
e.
that the bacterium can make its own leucine.
13. thr refers to a gene that governs a cells ability to synthesize threonine from inorganic precursors. The
designation thr+ indicates:
a.
that the allele is normal.
b.
that the allele is the mutant allele.
c.
that the bacterium is biologically active.
d.
that the bacterium is biologically inactive.
e.
that the bacterium cannot make its own threonine.
14. If strain a and strain b conjugate, the most likely outcome of their offspring would be:
a.
bio- met- leu- thr- thi+.
b.
bio+ met+ leu- thr+ thi+.
c.
bio+ met- leu- thr- thi+.
d.
bio+ met+ leu- thr- thi+.
e.
bio- met- leu- thr- thi-
15. During bacterial conjugation, bacterial DNA with different alleles are transferred. Bacteria use a long
tubular structure called a ____ to obtain differing alleles.
a.
metabolic pilus
b.
asexual pilus
c.
flagellum
d.
cilia
e.
sex pilus
16. Conjugation is a process by which the bacterial cells
a.
contact each other using a sex pilus to obtain new alleles.
b.
contact each other for gratification purposes.
c.
disrupt each other
d.
are infected with virus
e.
a bacteriophage carries DNA from one bacterium to another.
17. The ability to conjugate depends on the presence within the donor cell of a plasmid called the ____.
a.
X factor
b.
F factor
c.
C factor
d.
sex pilus
e.
S factor
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TOP: 17.1 GENE TRANSFER AND GENETIC RECOMBINATION IN BACTERIA
18. Small circles of DNA that occur in bacteria in addition to the main circular chromosomal DNA
molecule are called:
a.
transformants.
b.
plastids.
c.
plasmids.
d.
plasmitrons.
e.
bacteriophage.
19. Donor cells in conjugation are labeled ____, whereas recipient cells are labeled ____.
a.
F+ cells; F- cells
b.
F+ cells; F+ cells
c.
F- cells; F+ cells
d.
F1 cells; F2 cells
e.
F+ cells; F2 cells
20. The purpose of the sex pilus is to:
a.
form a cytoplasmic bridge and conjugate.
b.
form a gap junction and conjugate.
c.
facilitate cytoplasmic exchange.
d.
allow bacteriophage infection.
e.
lyse the cell.
21. F+ X F- mating does not result in
a.
plasmid genetic recombination.
b.
chromosomal genetic recombination.
c.
circularization of DNA.
d.
conjugation.
e.
cell-cell contact via a sex pilus.
22. Hfr cells are cells that can integrate the F factor and some genes into the bacterial chromosome. Hfr
cells can do this through:
a.
mitosis.
b.
meiosis.
c.
prophase.
d.
crossing over.
e.
transduction.
23. Genetic recombination by conjugation was discovered by:
a.
Francois Jacob.
b.
Elie L. Wollman.
c.
Gregor Mendel.
d.
Francois Jacob and Elie L. Wollman
e.
Elie L. Wollman and Gregor Mendel
24. The full transfer of an entire DNA molecule to an F- cell would take about ____ minutes.
a.
10−20
b.
20−30
c.
300−400
d.
4−7
e.
90−100
Use the figure above for the following question(s).
25. In order to transfer gene a, b, and c to an F- cell, how long must the sex pilus be in place?
a.
Less than 4 minutes.
b.
10 minutes.
c.
14 minutes.
d.
More than 8 minutes but less than 20.
e.
5 minutes
26. In order to transfer gene a to an F- cell, the sex pilus must be in place for at least ____ minutes.
a.
1
b.
2
c.
3
d.
4
e.
5
27. In order to transfer all the genes to an F- cell we would need how long?
a.
1 minute
b.
20 minutes
c.
3 minutes
d.
14 minutes
e.
5 minutes
28. How long would it take to transfer genes a and b to an F- cell?
a.
1 minute
b.
7 minutes
c.
90 minutes
d.
4 minutes
e.
6 minutes
29. R plasmids
a.
provide antibiotic resistance.
b.
provide a fertility factor.
c.
provide reliance to bacteria.
d.
provide recombination to bacteria.
e.
provide nutrients.
30. In transformation, cells
a.
take up pieces of DNA that are released as other cells disintegrate.
b.
take up pieces of DNA through infection of a virus.
c.
replicate DNA molecules.
d.
make replicate copies of one another.
e.
generate their own DNA.
31. Transformation was discovered by:
a.
Francois Jacob.
b.
Elie L. Wollman.
c.
Gregor Mendel.
d.
Joshua Lederberg.
e.
Fred Griffith.
32. A colony of mice is treated with a noninfective form of the bacterium Streptococcus pneumoniae. A
new researcher exposes this noninfective form to heat-killed cells of an infective strain. What would
be the effect of this action in the mouse population?
a.
The mice will all remain healthy.
b.
Some mice will die, but most will live.
c.
The mice will get sick with pneumonia.
d.
Some will get sick with pneumonia, but most will live.
e.
The mice will become immune to the bacterium.
33. A colony of mice is treated with a noninfective form of the bacterium Streptococcus pneumoniae. A
researcher exposes this noninfective form to heat-killed cells of an infective strain. The bacterial cells
are said to be:
a.
transduced.
b.
artificially transformed.
c.
transformed.
d.
noninfectious.
e.
conjugated
34. The linear DNA fragments taken up from disrupted infective cells recombine with the chromosomal
DNA of the noninfective cells by ____, much in the same way as genetic recombination takes place in
conjugation.
a.
meiosis
b.
metaphase II
c.
nuclear division
d.
double crossovers
e.
transformation
35. Bacterial cells that cannot readily pick up DNA molecules from their surroundings can be forced to do
so by ____.
a.
artificial transformation
b.
double crossing over
c.
crossing over
d.
constriction
e.
infection
36. Exposing E. coli to calcium ions, then incubating the culture at low temperatures and finally heat
shocking the culture will accomplish:
a.
artificial transformation.
b.
double crossing over.
c.
crossing over.
d.
constriction.
e.
infection.
37. A technique that is used to artificially transform a bacterium is called electroporation. Electroporation:
a.
exposes cells briefly to rapid pulses of electrical current.
b.
exposes cells to calcium ions.
c.
exposes cells to stomes.
d.
inserts the foreign DNA into the DNA in the chloroplast.
e.
inserts the foreign DNA into the plant’s mitochondrial DNA.
38. In transduction, bacterial cells
a.
take up pieces of DNA that are released as other cells disintegrate.
b.
take up pieces of DNA through the use of a virus.
c.
replicate DNA molecules.
d.
make replicate copies of one another.
e.
generate their own DNA.
39. Transduction was discovered in 1952 by this Nobel Prize winner.
a.
Francois Jacob
b.
Elie L. Wollman
c.
Gregor Mendel
d.
Joshua Lederberg
e.
Fred Griffith
40. Norton Zinder and Joshua Lederberg used this microorganism to understand transduction.
a.
Escherichia coli
b.
Neurospora
c.
Aspergillus
d.
Salmonella typhimurium
e.
Streptococcus pneumoniae
41. A plate of solid growth medium with colonies on it is pressed gently onto sterile velveteen. The
velveteen “stamp” is used to make identical plates. This technique is called:
a.
replication.
b.
replica plating.
c.
plating.
d.
plate making.
e.
horizontal gene transfer
42. Media that contain a full complement of nutrient substances, including amino acids, and other
chemicals that normal strains use for themselves, is called:
a.
agar media.
b.
minimal medium.
c.
nutritious media.
d.
complete medium.
e.
rich media.
43. A researcher is looking for met- strains. He/she compares two plates. One plate has colonies growing
on complete medium. The other plate has colonies growing on methionine deficient medium. How can
the researcher determine which colonies are met-?
a.
The colonies growing on the methionine plate are met-.
b.
met- colonies grow on the complete medium but do not grow on the plate lacking
methionine.
c.
We cannot determine which colonies are met- because we do not have enough
information.
d.
Only the colonies growing on the complete medium are met-.
e.
met- colonies grow on the plate lacking methionine but do not grow on the complete
medium.
44. Viruses can undergo genetic recombination when
a.
the DNA of one virus infects a single cell.
b.
bacterial DNA enters a bacterium.
c.
one virus infects a second virus
d.
the DNA of two viruses infect a single cell.
e.
bacterial DNA enters a virus
45. Viruses are composed of only
a.
proteins.
b.
carbohydrates and proteins.
c.
proteins and nucleic acids.
d.
nucleic acids.
e.
carbohydrates, proteins, lipids, and nucleic acids.
46. The core of a virus is
a.
a protein.
b.
a sugar.
c.
a nucleic acid.
d.
a fat.
e.
a phosphate.
47. When viruses are not inside a cell, they are carried about passively by random molecular movements
and perform none of the metabolic activities of ____.
a.
homeostasis.
b.
life.
c.
eukaryotes.
d.
prokaryotes.
e.
autotrophs.
48. All viruses have genes encoding at least:
a.
their coat proteins.
b.
enzymes required for nucleic acid replication.
c.
their coat proteins and enzymes required for nucleic acid replication.
d.
a plasma membrane.
e.
their coat proteins and a plasma membrane.
49. Viruses that kill their host cells during each cycle of infection are called
a.
virulent bacteriophages.
b.
bacteriophages.
c.
temperate bacteriophages.
d.
phages.
e.
avirulent bacteriophages.
50. Viruses that enter an inactive phase in which the host cell replicates and passes on a bacteriophage
DNA for generations before the phage becomes active and kills the host are called
a.
virulent bacteriophages.
b.
bacteriophages.
c.
temperate bacteriophages.
d.
phages.
e.
avirulent bacteriophages.
51. T-even bacteriophages infect
a.
Escherichia coli.
b.
Neurospora.
c.
Aspergillus.
d.
Salmonella typhimurium.
e.
Streptococcus pneumoniae.
52. The series of events from infection of one cell through the release of progeny phages from broken,
open, or lysed cells is called
a.
lytic cycle.
b.
lysogenic cycle.
c.
Krebs cycle.
d.
citric acid cycle.
e.
lytic or lysogenic cycle.
53. For some virulent phages, fragments of the host DNA may be included in the heads as the viral
particles assemble, providing the basis for transduction of bacterial genes during the next cycle of
infection. This mechanism is termed:
a.
transformation.
b.
transmutation.
c.
metabolism.
d.
specific transduction.
e.
generalized transduction.
54. Bacteriophage lambda
a.
is a temperate phage.
b.
is a virulent phage.
c.
is used in plants.
d.
is used in animals.
e.
is a T-even phage
55. This cycle begins when the lambda circular chromosome integrates into the host cell’s DNA by
crossing over. Once integrated, the lambda genes are mostly inactive. This cycle is referred as
a.
lytic cycle.
b.
lysogenic cycle.
c.
Krebs cycle.
d.
citric acid cycle.
e.
lytic or lysogenic cycle.
56. A virus in the lysogenic cycle is referred to as a
a.
prophage.
b.
virulent phage.
c.
tempered phage.
d.
T-even phage.
e.
lytic phage.
57. Put the following steps of the HIV life cycle in order:
1.Viral RNAs and proteins assemble into new viral particles that bud from the cell.
2.DNA copy of the viral genome is integrated into the host genome.
3.Viral reverse transcriptase makes a DNA copy of the viral RNA genome.
4.Viral particle enters the cell.
5.The provirus is transcribed into viral RNA genomes and mRNAs to make viral proteins.
a.
3,2,5,1,4
b.
2,3,4,5,1
c.
4,2,3,1,5
d.
2,4,3,5,1
e.
4,3,2,5,1
58. Viroids
a.
are more complex than viruses
b.
have large DNA genomes
c.
encode their own polymerase for nucleic acid replication
d.
cause diseases in plants
e.
infect animal cells
59. Prions
a.
are more complex than viruses
b.
have large DNA genomes
c.
cause neurodegenerative disorders in mammals
d.
infect plant cells
e.
encode their own polymerases for nucleic acid replication
60. When David Baltimore’s lab tried to determine how an RNA tumor virus replicates its genome, they
discovered that
a.
these viruses can make DNA without an RNA template
b.
these viruses can make DNA after being treated with RNase
c.
these viruses can make more RNA genomes from their RNA genome
d.
an enzyme (reverse transcriptase) makes DNA from RNA
e.
an enzyme (reverse transcriptase) makes RNA from DNA
61. According to research done by Baron, Caughey, and Prado, how do prions move within the brain?
a.
They use receptors on the surfaces of nerve cells.
b.
They use vesicles found inside the nerve cells.
c.
They use tunneling nanotubes.
d.
They pinch off the nerve cell membrane.
e.
They stick to the outer surfaces of nerve cells.
MATCHING
Match each of the following terms with its correct definition.
a.
For some virulent phages, fragments of the host DNA may be included in the heads as the
viral particles assemble, providing the basis for transduction of bacterial genes during the
next cycle of infection.
b.
A virus
c.
This cycle begins when the lambda circular chromosome integrates into the host cell’s
DNA by crossing over. Once integrated, the lambda genes are mostly inactive.
d.
Type of virus that does not kill a host cell in every replication cycle
e.
Type of virus that kills a host cell in every replication cycle
f.
When only genes that are adjacent to the integration site of a temperate phage can be cut
out with the viral DNA and included in phage particles during the lytic stage.
g.
When an animal virus remains in the cell in an inactive form.
h.
Enzyme that can make DNA from RNA.
i.
The series of events from infection of one cell through the release of progeny phages from
broken, open, or lysed cells.
j.
Virus with an RNA genome that is copied into DNA.
k.
Integrated bacteriophage.
l.
Includes phages such as T2 and T4.
m.
Layer of protein surrounding the viral nucleic acid.
n.
Enzyme that uses an RNA template to make a DNA copy of the retrotransposon.
o.
Transferring DNA using a virus.
p.
E. coli phage.
62. lytic pathway
63. lysogenic pathway
64. transduction
65. phage
66. virulent phage
67. temperate phage
379
68. generalized transduction
69. specialized transduction
70. latent phase
71. reverse transcriptase
72. retrovirus
73. prophage
74. T-even bacteriophages
75. reverse transcriptase
76. capsid
77. bacteriophage lambda
380
SHORT ANSWER
78. After conjugation between an F+ cell and an F- cell, is the F- cell F- or F+? After conjugation between
an Hfr cell and an F- cell, is the F- cell F- or F+? Explain each answer.
79. Conjugation, transduction, and transformation are the three main mechanisms for gene transfer
between bacteria. Compare these three mechanisms in terms of how DNA is transferred.
80. A bacterial cell that is bio- met- leu+ thr- thi+ is infected by a virus carrying bacterial DNA containing
bio+ met+ leu- thr- thi+. If all five genes from the virally transduced DNA are recombined into the
recipient cell, what kinds of nutrients will the resulting cell still require from the medium in order to
grow?
81. What is the main difference between a virulent bacteriophage and a temperate bacteriophage?
82. What makes a prion unique as an infectious particle?