1) Viral envelopes can best be analyzed with which of the following
techniques?
A) use of 15N to label specific nucleotides
B)
antibodies against specific proteins not found in the host
membranes
C) DNA staining and visualization with the light
microscope
D) use of plaque assays for quantitative measurement
of viral titer
E) immunofluorescent tagging of capsid proteins
b
2) The host range of a virus is determined by
A) the enzymes
carried by the virus.
B) whether its nucleic acid is DNA or
RNA.
C) the proteins in the host's cytoplasm.
D) the
enzymes produced by the virus before it infects the cell.
E) the
proteins on its surface and that of the host.
e
3) Which of the following accounts for someone who has had a
herpesvirus-mediated cold sore
or genital sore getting flare-ups
for the rest of his or her life?
A) re-infection by a closely
related herpesvirus of a different strain
B) re-infection by the
same herpesvirus strain
C) co-infection with an unrelated virus
that causes the same symptoms
D) copies of the herpesvirus genome
permanently maintained in host nuclei
E) copies of the
herpesvirus genome permanently maintained in host cell cytoplasm
d
4) In many ways, the regulation of the genes of a particular group of
viruses will be similar to the
regulation of the host genes.
Therefore, which of the following would you expect of the genes
of
the bacteriophage?
A) regulation via acetylation of
histones
B) positive control mechanisms rather than
negative
C) control of more than one gene in an operon
D)
reliance on transcription activators
E) utilization of eukaryotic polymerases
c
5) Which of the following is characteristic of the lytic
cycle?
A) Many bacterial cells containing viral DNA are
produced.
B) Viral DNA is incorporated into the host
genome.
C) The viral genome replicates without destroying the
host.
D) A large number of phages are released at a time.
E)
The virus-host relationship usually lasts for generations.
d
6) Which of the following statements describes the lysogenic cycle of
lambda (λ) phage?
A) After infection, the viral genes immediately
turn the host cell into a lambda-producing
factory, and the host
cell then lyses.
B) Most of the prophage genes are activated by
the product of a particular prophage gene.
C) The phage genome
replicates along with the host genome.
D) Certain environmental
triggers can cause the phage to exit the host genome, switching
from
the lytic to the lysogenic.
E) The phage DNA is
incorporated by crossing over into any nonspecific site on the host cell's
DNA.
c
7) Most molecular biologists think that viruses originated from
fragments of cellular nucleic
acid. Which of the following
observations supports this theory?
A) Viruses contain either DNA
or RNA.
B) Viruses are enclosed in protein capsids rather than
plasma membranes.
C) Viruses can reproduce only inside host
cells.
D) Viruses can infect both prokaryotic and eukaryotic
cells.
E) Viral genomes are usually similar to the genome of the
host cell.
e
8) A researcher lyses a cell that contains nucleic acid molecules and
capsomeres of tobacco
mosaic virus (TMV). The cell contents are
left in a covered test tube overnight. The next day this
mixture
is sprayed on tobacco plants. Which of the following would be expected
to occur?
A) The plants would develop some but not all of the
symptoms of the TMV infection.
B) The plants would develop
symptoms typically produced by viroids.
C) The plants would
develop the typical symptoms of TMV infection.
D) The plants
would not show any disease symptoms.
E) The plants would become
infected, but the sap from these plants would be unable to
infect
other plants.
c
9) Which viruses have single-stranded RNA that acts as a template for
DNA synthesis?
A) lytic phages
B) proviruses
C)
viroids
D) bacteriophages
E) retroviruses
e
10) What is the function of reverse transcriptase in
retroviruses?
A) It hydrolyzes the host cell's
DNA.
B) It uses viral RNA as a template for DNA
synthesis.
C) It converts host cell RNA into viral DNA.
D)
It translates viral RNA into proteins.
E) It uses viral RNA as a
template for making complementary RNA strands.
b
11) Why do RNA viruses appear to have higher rates of
mutation?
A) RNA nucleotides are more unstable than DNA
nucleotides.
B) Replication of their genomes does not involve
proofreading.
C) RNA viruses replicate faster.
D) RNA
viruses can incorporate a variety of nonstandard bases.
E) RNA
viruses are more sensitive to mutagens.
b
12) Which of the following can be effective in preventing the onset
of viral infection in humans?
A) taking vitamins
B) getting
vaccinated
C) taking antibiotics
D) applying
antiseptics
E) taking nucleoside analogs that inhibit transcription
b
13) Which of the following describes plant virus infections?
A)
They can be controlled by the use of antibiotics.
B) They are
spread via the plasmodesmata.
C) They have little effect on plant
growth.
D) They are seldom spread by insects.
E) They can
never be passed vertically.
b
14) The difference between vertical and horizontal transmission of
plant viruses is that
A) vertical transmission is transmission of
a virus from a parent plant to its progeny, and
horizontal
transmission is one plant spreading the virus to another
plant.
B) vertical transmission is the spread of viruses from the
upper leaves to the lower leaves of the
plant, and horizontal
transmission is the spread of a virus among leaves at the same general
level.
C) vertical transmission is the spread of viruses from
trees and tall plants to bushes and other
smaller plants, and
horizontal transmission is the spread of viruses among plants of
similar size.
D) vertical transmission is the transfer of DNA
from one type of plant virus to another, and
horizontal
transmission is the exchange of DNA between two plant viruses of the
same type.
E) vertical transmission is the transfer of DNA from a
plant of one species to a plant of a
different species, and
horizontal transmission is the spread of viruses among plants of the same
species.
a
15) Which of the following is the best predictor of how much damage a
virus causes?
A) ability of the infected cell to undergo normal
cell division
B) ability of the infected cell to carry on
translation
C) whether the infected cell produces viral
protein
D) whether the viral mRNA can be transcribed
E) how
much toxin the virus produces
a
16) Antiviral drugs that have become useful are usually associated
with which of the following
properties?
A) ability to remove
all viruses from the infected host
B) interference with viral
replication
C) prevention of the host from becoming
infected
D) removal of viral proteins
E) removal of viral mRNAs
b
17) Which of the following series best reflects what we know about
how the flu virus moves
between species?
A) An avian flu
virus undergoes several mutations and rearrangements such that it is
able to be
transmitted to other birds and then to humans.
B)
The flu virus in a pig is mutated and replicated in alternate
arrangements so that humans who
eat the pig products can be
infected.
C) A flu virus from a human epidemic or pandemic
infects birds; the birds replicate the virus
differently and then
pass it back to humans.
D) An influenza virus gains new sequences
of DNA from another virus, such as a herpesvirus;
this enables it
to be transmitted to a human host.
E) An animal such as a pig is
infected with more than one virus, genetic recombination
occurs,
the new virus mutates and is passed to a new species such
as a bird, and the virus mutates and
can be transmitted to humans.
e
18) Which of the following is the most probable fate of a newly
emerging virus that causes high
mortality in its host?
A) It
is able to spread to a large number of new hosts quickly because the
new hosts have no
immunological memory of them.
B) The new
virus replicates quickly and undergoes rapid adaptation to a series of
divergent hosts.
C) A change in environmental conditions such as
weather patterns quickly forces the new virus
to invade new
areas.
D) Sporadic outbreaks will be followed almost immediately
by a widespread pandemic.
E) The newly emerging virus will die
out rather quickly or will mutate to be far less lethal.
e
1) Which of the three types of viruses shown in Figure 17.1 would you
expect to include
glycoproteins?
A) I only
B) II
only
C) III only
D) I and II only
E) all three
d
2) Which of the three types of viruses shown in Figure 17.1 would you
expect to include a
capsid(s)?
A) I only
B) II
only
C) III only
D) I and II only
E) all three
e
3) In Figure 17.2, at the arrow marked II, what enzyme(s) are being
utilized?
A) reverse transcriptase
B) viral DNA
polymerase
C) host cell DNA polymerase
D) host cell RNA
polymerase
E) host cell DNA and RNA polymerases
c
4) In Figure 17.2, when new viruses are being assembled (IV), what
mediates the assembly?
A) host cell chaperones
B) assembly
proteins coded for by the host nucleus
C) assembly proteins coded
for by the viral genes
D) viral RNA intermediates
E)
nothing; they self-assemble
e
5) Based on Table 17.1, which virus meets the Baltimore requirements
for a retrovirus?
A) A
B) B
C) C
D) D
E) E
d
6) Based on Table 17.1, which virus meets the requirements for a
bacteriophage?
A) A
B) B
C) C
D) D
E) E
a
Some viruses can be crystallized and their structures analyzed. One
such virus is yellow mottle
virus, which infects beans. This
virus has a single-stranded RNA genome containing about
6,300
nucleotides. Its capsid is 25-30 nm in diameter and
contains 180 identical capsomeres.
1) If the yellow mottle virus
capsid has 20 facets, how many proteins form each facet?
A)
1
B) 5
C) 9
D) 20
E) 180
c
You isolate an infectious substance that is capable of causing
disease in plants, but you do not
know whether the infectious
agent is a bacterium, virus, viroid, or prion. You have four
methods
at your disposal that you can use to analyze the
substance in order to determine the nature of the
infectious
agent.
I. treating the substance with nucleases that destroy all
nucleic acids
and then determining whether it is still
infectious
II. filtering the substance to remove all elements
smaller than what can
be easily seen under a light
microscope
III. culturing the substance by itself on nutritive
medium, away from
any plant cells
IV. treating the sample
with proteases that digest all proteins and then
determining
whether it is still infectious
2) If you already knew that the
infectious agent was either bacterial or viral, which
treatment
would allow you to distinguish between these two
possibilities?
A) I
B) II
C) III
D) IV
E)
either II or IV
c
3) If you already knew that the infectious agent was either a viroid
or a prion, which treatment
would allow you to distinguish
between these two possibilities?
A) I only
B) II
only
C) III only
D) IV only
E) either I or IV
e
The herpesviruses are very important enveloped DNA viruses that cause
disease in all vertebrate
species and in some invertebrates such
as oysters. Some of the human ones are herpes simplex
virus (HSV)
types I and II, causing facial and genital lesions, and the varicella
zoster virus
(VSV), causing chicken pox and shingles. Each of
these three actively infects nervous tissue.
Primary infections
are fairly mild, but the virus is not then cleared from the host;
rather, viral
genomes are maintained in cells in a latent phase.
The virus can then reactivate, replicate again,
and be infectious
to others.
4) If scientists are trying to use what they know
about HSV to devise a means of protecting other
people from being
infected, which of the following would have the best chance of
lowering the
number of new cases of infection?
A)
vaccination of all persons with preexisting cases
B) interference
with new viral replication in preexisting cases
C) treatment of
the HSV lesions to shorten the breakout
D) medication that
destroys surface HSV before it gets to neurons
E) education about
avoiding sources of infection
b
5) In electron micrographs of HSV infection, it can be seen that the
intact virus initially reacts
with cell-surface proteoglycans,
then with specific receptors. This is later followed by
viral
capsids docking with nuclear pores. Afterward, the capsids
go from being full to being "empty."
Which of
the following best fits these observations?
A) Viral capsids are
needed for the cell to become infected; only the capsids enter the
nucleus.
B) The viral envelope is not required for infectivity,
since the envelope does not enter the
nucleus.
C) Only the
genetic material of the virus is involved in the cell's
infectivity, and is injected like
the genome of a phage.
D)
The viral envelope mediates entry into the cell, the capsid enters
into the nuclear membrane,
and the genome is all that enters the
nucleus.
E) The viral capsid mediates entry into the cell, and
only the genomic DNA enters the nucleus,
where it may or may not replicate.
d
6) In order to be able to remain latent in an infected live cell, HSV
must be able to shut down
what process?
A) DNA
replication
B) transcription of viral genes
C) apoptosis of
a virally infected cell
D) all immune responses
E)
interaction with histones
c
1) Which of the following characteristics, structures, or processes
is common to both bacteria
and viruses?
A)
metabolism
B) ribosomes
C) genetic material composed of
nucleic acid
D) cell division
E) independent existence
c
2) Emerging viruses arise by
A) mutation of existing
viruses.
B) the spread of existing viruses to new host
species.
C) the spread of existing viruses more widely within
their host species.
D) all of the above
E) none of the above
d
3) A human pandemic is
A) a viral disease that infects all
humans.
B) a flu that kills more than 1 million people.
C)
an epidemic that extends around the world.
D) a viral disease
that can infect multiple species.
E) a virus that increases in
mortality rate as it spreads.
c
4) A bacterium is infected with an experimentally constructed
bacteriophage composed of the T2
phage protein coat and T4 phage
DNA. The new phages produced will have
A) T2 protein and T4
DNA.
B) T2 protein and T2 DNA.
C) a mixture of the DNA and
proteins of both phages.
D) T4 protein and T4 DNA.
E) T4
protein and T2 DNA.
d
5) RNA viruses require their own supply of certain enzymes
because
A) host cells rapidly destroy the viruses.
B) host
cells lack enzymes that can replicate the viral genome.
C) these
enzymes translate viral mRNA into proteins.
D) these enzymes
penetrate host cell membranes.
E) these enzymes cannot be made in
host cells.
b
1) What is metagenomics?
A) genomics as applied to a species
that most typifies the average phenotype of its genus
B) the
sequence of one or two representative genes from several
species
C) the sequencing of only the most highly conserved genes
in a lineage
D) sequencing DNA from a group of species from the
same ecosystem
E) genomics as applied to an entire phylum
d
2) Which procedure is not required when the shotgun approach to
sequencing is modified as
sequencing by synthesis, in which many
small fragments are sequenced simultaneously?
A) use of
restriction enzymes
B) sequencing each fragment
C) cloning
each fragment into a plasmid
D) ordering the sequences
E)
PCR amplification
c
3) What is proteomics?
A) the linkage of each gene to a
particular protein
B) the study of the full protein set encoded
by a genome
C) the totality of the functional possibilities of a
single protein
D) the study of how amino acids are ordered in a
protein
E) the study of how a single gene activates many proteins
b
4) What is bioinformatics?
A) a technique using 3-D images of
genes to predict how and when they will be expressed
B) the
application of computational methods to the storage and analysis of
biological data
C) software programs available from NIH to design
and synthesize genes
D) a series of search programs that allow a
student to identify which labs around the world are
trying to
sequence the genome of a given species
E) a procedure that uses
software to order DNA sequences in a variety of comparable ways
b
5) A microarray known as a GeneChip, with most of the human
protein-coding genetic
sequences, has been developed to aid in
the study of human cancer by first comparing two to
three subsets
of cancer subtypes. What kind of information might be gleaned from
this GeneChip
to aid in cancer prevention?
A) information
about whether or not a patient has this type of cancer prior to
treatment
B) evidence that might suggest how best to treat a
person's cancer with chemotherapy
C) data that could
alert patients to what kind of cancer they were likely to
acquire
D) information about which parent might have provided a
patient with cancer-causing genes
E) information on cancer
epidemiology in the United States or elsewhere
c
6) Which of the following most correctly describes the whole-genome
shotgun technique for
sequencing a genome?
A) genetic
mapping followed immediately by sequencing
B) physical mapping
followed immediately by sequencing
C) cloning large genome
fragments into very large vectors such as YACs, followed
by
sequencing
D) cloning fragments from many copies of an
entire chromosome, sequencing the fragments, and
then ordering
the sequences
E) cloning the whole genome directly, from one end
to the other
d
7) Which of the following is a representation of gene
density?
A) Humans have 2,900 Mb per genome.
B) C. elegans
has ~20,000 genes.
C) Humans have ~20,000 genes in 2,900
Mb.
D) Humans have 27,000 bp in introns.
E) Fritillaria has
a genome 40 times the size of a human genome.
c
8) Why might the cricket genome have 11 times as many base pairs as
that of Drosophila
melanogaster?
A) The two insect species
evolved in very different geologic eras.
B) Crickets have higher
gene density.
C) Drosophila are more complex organisms.
D)
Crickets must have more noncoding DNA.
E) Crickets must make many
more proteins.
d
9) The comparison between the number of human genes and those of
other animal species has
led to many conclusions, including
that
A) the density of the human genome is far higher than in
most other animals.
B) the number of proteins expressed by the
human genome is far more than the number of its
genes.
C)
most human DNA consists of genes for protein, tRNA, rRNA, and
miRNA.
D) the genomes of other organisms are significantly
smaller than the human genome.
b
10) What characteristic of short tandem repeat DNA makes it useful
for DNA fingerprinting?
A) The number of repeats varies widely
from person to person or animal to animal.
B) The sequence of DNA
that is repeated varies significantly from individual to
individual.
C) The sequence variation is acted upon differently
by natural selection in different
environments.
D) Every
racial and ethnic group has inherited different short tandem repeats.
a
11) In humans, the embryonic and fetal forms of hemoglobin have a
higher affinity for oxygen
than that of adults. This is due
to
A) nonidentical genes that produce different versions of
globins during development.
B) identical genes that generate many
copies of the ribosomes needed for fetal globin production.
C)
pseudogenes, which interfere with gene expression in adults.
D)
the attachment of methyl groups to cytosine following birth, which
changes the type of
hemoglobin produced.
E) histone proteins
changing shape during embryonic development.
a
12) A multigene family is composed of
A) multiple genes whose
products must be coordinately expressed.
B) genes whose sequences
are very similar and that probably arose by duplication.
C) the
many tandem repeats such as those found in centromeres and
telomeres.
D) a gene whose exons can be spliced in a number of
different ways.
E) a highly conserved gene found in a number of
different species.
b
13) Which of the following can be duplicated in a genome?
A) DNA
sequences above a minimum size only
B) DNA sequences below a
minimum size only
C) entire chromosomes only
D) entire sets
of chromosomes only
E) sequences, chromosomes, or sets of chromosomes
e
14) Unequal crossing over during prophase I can result in one sister
chromosome with a deletion
and another with a duplication. A
mutated form of hemoglobin, so-called hemoglobin Lepore,
exists
in the human population. Hemoglobin Lepore has a deleted series of
amino acids. If this
mutated form was caused by unequal crossing
over, what would be an expected consequence?
A) If it is still
maintained in the human population, hemoglobin Lepore must be selected
for in
evolution.
B) There should also be persons whose
hemoglobin contains two copies of the series of amino
acids that
is deleted in hemoglobin Lepore.
C) Each of the genes in the
hemoglobin gene family must show the same deletion.
D) The
deleted gene must have undergone exon shuffling.
E) The deleted
region must be located in a different area of the individual's genome.
b
15) Humans have 23 pairs of chromosomes. In contrast, chimpanzees
have 24 pairs of
chromosomes and lack any pair resembling the
long human chromosome 2 pair; instead,
chimpanzees have two pairs
of medium-sized chromosomes. What is the most likely
explanation
for these differences in the human and chimpanzee
genomes?
A) The common ancestor of humans and chimpanzees had 24
pairs of chromosomes, and at
some point in the human lineage, two
chromosomes fused end to end, providing some
selective
advantage.
B) The common ancestor of humans and
chimpanzees had 23 pairs of chromosomes, but when
chimpanzees
evolved, one of the chromosomes broke in half.
C) At some point
in evolution, human ancestors and chimpanzee ancestors were able to
mate and
produce fertile offspring, making a new species.
D)
Chromosome breakage resulted in additional centromeres being made,
allowing meiosis to
proceed successfully.
E) Transposable
elements transferred significantly large segments of the chromosomes
to new
locations.
a
16) When does exon shuffling occur?
A) during splicing of
DNA
B) during DNA replication
C) during meiotic
recombination
D) during post-translational modification of
proteins
E) during faulty DNA repair
c
17) In order to determine the probable function of a particular
sequence of DNA in humans, what
might be the most reasonable
approach?
A) Prepare a knockout mouse without a copy of this
sequence and examine the mouse
phenotype.
B) Genetically
engineer a mouse with a copy of this sequence and examine its
phenotype.
C) Look for a reasonably identical sequence in another
species, prepare a knockout of this
sequence in that species, and
look for the consequences.
D) Prepare a genetically engineered
bacterial culture with the sequence inserted and assess which
new
protein is synthesized.
E) Mate two individuals heterozygous for
the normal and mutated sequences.
c
18) Homeotic genes contain a homeobox sequence that is highly
conserved among very diverse
species. The homeobox is the code
for that domain of a protein that binds to DNA in a
regulatory
developmental process. Which of the following would
you then expect?
A) that homeotic genes are selectively expressed
over developmental time
B) that a homeobox-containing gene has to
be a developmental regulator
C) that homeoboxes cannot be
expressed in nonhomeotic genes
D) that all organisms must have
homeotic genes
E) that all organisms must have
homeobox-containing genes
a
19) A recent study compared the H. sapiens genome with that of
Neanderthals. The results of the
study indicated that there was a
mixing of the two genomes at some period in evolutionary
history.
The data that suggested this were
A) some Neanderthal sequences
not found in humans.
B) a number of modern H. sapiens with
Neanderthal sequences.
C) Neanderthal Y chromosomes preserved in
the modern population of males.
D) mitochondrial sequences common
to both groups.
b
20) Fragments of DNA have been extracted from the remnants of extinct
woolly mammoths,
amplified, and sequenced. These can now be used
to
A) introduce into relatives, such as elephants, certain
mammoth traits.
B) clone live woolly mammoths.
C) study the
relationships among woolly mammoths and other wool-producers.
D)
understand the evolutionary relationships among members of related
taxa.
E) appreciate the reasons why mammoths went extinct.
d
The pie chart in Figure 18.1 represents the relative frequencies of
the following in the human
genome:
I. repetitive DNA
unrelated to transposons
II. repetitive DNA that includes
transposons
III. unique noncoding DNA
IV. introns and
regulatory sequences
V. exons
1) Which region is occupied by
exons only (V)?
A) A
B) B
C) C
D) D
E) E
a
2) Which region includes Alu elements and LI sequences?
A)
A
B) B
C) C
D) D
E) E
e
3) The movement of these blocks suggests that
A) during
evolutionary time, these sequences have separated and have returned to
their original
positions.
B) DNA sequences within these
blocks have become increasingly divergent.
C) sequences
represented have duplicated at least three times.
D) chromosomal
translocations have moved blocks of sequences to other
chromosomes.
E) higher mammals have more convergence of gene
sequences related in function.
d
4) Which of the following represents another example of the same
phenomenon as that shown in
Figure 18.2?
A) the apparent
centric fusion between two chromosome pairs of primates such as chimps
to
form the ancestor of human chromosome 2
B) the difference
in the numbers of chromosomes in five species of one genus of
birds
C) the formation of several pseudogenes in the globin gene
family subsequent to human
divergence from other primates
D)
the high frequency of polyploidy in many species of angiosperms
a
Multigene families include two or more nearly identical genes or
genes sharing nearly identical
sequences. A classical example is
the set of genes for globin molecules, including genes on
human
chromosomes 11 and 16.
1) How might identical and obviously
duplicated gene sequences have gotten from one
chromosome to
another?
A) by normal meiotic recombination
B) by normal
mitotic recombination between sister chromatids
C) by
transcription followed by recombination
D) by chromosomal
translocation
E) by deletion followed by insertion
d
2) Several of the different globin genes are expressed in humans, but
at different times in
development. What mechanism could allow for
this?
A) exon shuffling
B) intron activation
C)
pseudogene activation
D) differential translation of
mRNAs
E) differential gene regulation over time
e
1) Bioinformatics includes all of the following except
A) using
computer programs to align DNA sequences.
B) analyzing protein
interactions in a species.
C) using molecular biology to combine
DNA from two different sources in a test tube.
D) developing
computer-based tools for genome analysis.
E) using mathematical
tools to make sense of biological systems.
c
2) One of the characteristics of retrotransposons is that
A)
they code for an enzyme that synthesizes DNA using an RNA
template.
B) they are found only in animal cells.
C) they
generally move by a cut-and-paste mechanism.
D) they contribute a
significant portion of the genetic variability seen within a
population of
gametes.
E) their amplification is dependent
on a retrovirus.
a
3) Homeotic genes
A) encode transcription factors that control
the expression of genes responsible for specific
anatomical
structures.
B) are found only in Drosophila and other
arthropods.
C) are the only genes that contain the homeobox
domain.
D) encode proteins that form anatomical structures in the
fly.
E) are responsible for differentiation in muscle cells.
a
4) Two eukaryotic proteins have one domain in common but are
otherwise very different. Which
of the following processes is
most likely to have contributed to this similarity?
A) gene
duplication
B) alternative splicing
C) exon
shuffling
D) histone modification
E) random point mutations
c
5) Two eukaryotic proteins are identical except for one domain in
each protein, and these two
domains are completely different from
each other. Which of the following processes is most
likely to
have contributed to this difference?
A) gene duplication
B)
alternative splicing
C) exon shuffling
D) histone
modification
E) random point mutations
b