Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
Which of the following is most likely a product of an early gene?
1)
A)
spike proteins
B)
DNA polymerase
C)
lysozyme
D)
envelope proteins
E)
capsid proteins
2)
How do all viruses differ from bacteria?
2)
A)
Viruses are not composed of cells.
B)
Viruses do not have any nucleic acid.
C)
Viruses are filterable.
D)
Viruses do not reproduce.
E)
Viruses are obligate intracellular parasites.
3)
Which of the following would be the first step in biosynthesis of a virus with a – (minus) strand of
RNA?
3)
A)
synthesis of double–stranded RNA from a DNA template
B)
synthesis of double–stranded RNA from an RNA template
C)
synthesis of DNA from a DNA template
D)
synthesis of DNA from an RNA template
E)
transcription of mRNA from DNA
4)
The mechanism whereby an enveloped virus leaves a host cell is called
4)
A)
budding.
B)
lysogeny.
C)
penetration.
D)
transduction.
E)
abduction.
5)
Which of the following is NOT utilized to culture viruses?
5)
A)
animal cell cultures
B)
embryonated eggs
C)
culture media
D)
laboratory animals
E)
bacterial cultures
6)
A viroid is a(n)
6)
A)
infectious protein.
B)
provirus.
C)
capsid without nucleic acid.
D)
complete, infectious virus particle.
E)
infectious piece of RNA without a capsid.
7)
Viruses that utilize reverse transcriptase belong to the virus families
7)
A)
Herpesviridae and Poxviridae.
B)
Rhabdoviridae and Herpesviridae.
C)
Retroviridae and Picornaviridae.
D)
Hepadnaviridae and Retroviridae.
E)
Herpesviridae and Retroviridae.
8)
An example of a latent viral infection is
8)
A)
cold sores.
B)
subacute sclerosing panencephalitis.
C)
influenza.
D)
smallpox.
E)
mumps.
9)
A lytic virus has infected a patient. Which of the following would best describe what is happening
inside the patient?
9)
A)
The virus is infecting cells and then releasing only small amounts of virus.
B)
The virus is not killing any cells in the host.
C)
The virus is causing the death of the infected cells in the patient.
D)
The virus is incorporating its nucleic acid with that of the patient’s cells.
E)
The virus is slowly killing the patient’s cells.
10)
Oncogenic viruses
10)
A)
are genetically unstable.
B)
cause acute infections.
C)
have no effect on the host cell.
D)
are lytic viruses that kill the host cell.
E)
cause tumors to develop.
11)
Which of the following places these items in the correct order for DNA–virus replication?
1. Maturation
2. DNA synthesis
3. Transcription
4. Translation
11)
A)
1; 2; 3; 4
B)
3; 4; 1; 2
C)
2; 3; 4; 1
D)
4; 1; 2; 3
E)
4; 3; 2; 1
12)
The following steps occur during biosynthesis of a + strand RNA virus. What is the third step?
12)
A)
penetration and uncoating
B)
synthesis of – strand RNA
C)
synthesis of viral proteins
D)
attachment
E)
synthesis of + strand RNA
13)
DNA made from an RNA template will be incorporated into the virus capsid of
13)
A)
Herpesviridae.
B)
Retroviridae.
C)
Hepadnaviridae.
D)
influenzavirus.
E)
bacteriophage families.
14)
A persistent infection is one in which
14)
A)
viral replication is unusually slow.
B)
the disease process occurs gradually over a long period.
C)
the virus remains in equilibrium with the host without causing a disease.
D)
host cells are gradually lysed.
E)
host cells are transformed.
15)
Generally, in an infection caused by a DNA–containing virus, the host animal cell supplies all of
the following EXCEPT
15)
A)
tRNA.
B)
nucleotides.
C)
RNA polymerase.
D)
DNA polymerase.
E)
None of the answers are correct; all of these are supplied by the host animal cell.
16)
The definition of lysogeny is
16)
A)
the period during replication when virions are not present.
B)
phage DNA is incorporated into host cell DNA.
C)
attachment of a phage to a cell.
D)
lysis of the host cell due to a phage.
E)
when the burst time takes an unusually long time.
17)
Bacteriophages and animal viruses do NOT differ significantly in which one of the following steps?
17)
A)
uncoating
B)
attachment
C)
release
D)
penetration
E)
biosynthesis
E
18)
Bacteriophage replication differs from animal virus replication because only bacteriophage
replication involves
18)
A)
injection of naked nucleic acid into the host cell.
B)
replication of viral nucleic acid.
C)
adsorption to specific receptors.
D)
lysis of the host cell.
E)
assembly of viral components.
A
19)
Which of the following statements about viral spikes is FALSE?
19)
A)
They are composed of carbohydrate–protein complexes.
B)
They bind to receptors on the host cell surface.
C)
They are used for attachment.
D)
They are found only on nonenveloped viruses.
E)
They may cause hemagglutination.
D
B
20)
Bacteriophages derive all of the following from the host cell EXCEPT
20)
A)
lysozyme.
B)
ATP.
C)
tRNA.
D)
amino acids.
E)
nucleotides.
21)
Which of the following statements is FALSE?
21)
A)
A prophage can “pop” out of the chromosome.
B)
A prophage may result in new properties of the host cell.
C)
A prophage is phage DNA inserted into a bacterial chromosome.
D)
The prophage makes the host cell immune to infection by other phages.
E)
Prophage genes are repressed by a repressor protein coded for by the prophage.
22)
Most RNA viruses carry which of the following enzymes?
22)
A)
ATP synthase
B)
DNA–dependent DNA polymerase
C)
reverse transcriptase
D)
RNA–dependent RNA polymerase
E)
lysozyme
23)
Assume you have isolated an unknown virus. This virus has a single, positive sense strand of
RNA, and possesses an envelope. To which group does it most likely belong?
23)
A)
togavirus
B)
herpesvirus
C)
picornavirus
D)
papovavirus
E)
retrovirus
24)
An envelope is acquired during which of the following steps?
24)
A)
penetration
B)
release
C)
uncoating
D)
biosynthesis
E)
adsorption
25)
In Figure 13.1, which structure is a complex virus?
25)
A)
a
B)
b
C)
c
D)
d
E)
All of the structures are complex viruses.
B
26)
What contributes to antigenic shift in influenza viruses?
26)
A)
attachment spikes
B)
different virus subtypes
C)
a segmented genome
D)
ease of virus transmission
E)
worldwide distribution of the virus
C
B
27)
The following steps occur during multiplication of retroviruses. Which is the fourth step?
27)
A)
penetration
B)
uncoating
C)
synthesis of double–stranded DNA
D)
attachment
E)
synthesis of +RNA
28)
Which of the following statments is NOT true of lysogeny?
28)
A)
Prophage is inserted into the host genome.
B)
Lytic cycle may follow lysogeny.
C)
It is a “silent” infection; the virus does not replicate.
D)
It causes lysis of host cells.
E)
It can give infected pathogens the genetic information for toxin production.
29)
Continuous cell lines differ from primary cell lines in that
29)
A)
continuous cell lines always have to be re–isolated from animal tissues.
B)
continuous cell lines can be maintained through an indefinite number of generations.
C)
viruses can be grown in continuous cell lines.
D)
continuous cell lines are from human embryos.
E)
continuous cell lines are derived from primary cell lines.
30)
An infectious protein is a
30)
A)
prion.
B)
papovavirus.
C)
retrovirus.
D)
bacteriophage.
E)
viroid.
Figure 13.1
31)
The structures illustrated in Figure 13.1 are composed of
31)
A)
DNA.
B)
Capsids.
C)
RNA.
D)
DNA or RNA.
E)
Capsomeres.
32)
Lysogeny can result in all of the following EXCEPT
32)
A)
immunity to reinfection by the same phage.
B)
immunity to reinfection by any phage.
C)
acquisition of new characteristics by the host cell.
D)
phage conversion.
E)
specialized transduction.
Figure 13.2
33)
Assume a patient has influenza. During which time on the graph in Figure 13.2 would the patient
show the symptoms of the illness?
33)
A)
a
B)
b
C)
c
D)
d
E)
e
34)
Some viruses, such as human herpesvirus 1, infect a cell without causing symptoms. These are
called
34)
A)
slow viruses.
B)
lytic viruses.
C)
unconventional viruses.
D)
phages.
E)
latent viruses.
35)
Which of the following is NOT used as a criterion to classify viruses?
35)
A)
morphology
B)
nucleic acid
C)
biochemical tests
D)
size
E)
number of capsomeres
36)
Assume a patient had chickenpox (human herpesvirus 3) as a child. Which line on the graph in
Figure 13.2 would show the number of viruses present in this person as a 60–year–old with
shingles (human herpesvirus 3)?
36)
A)
a
B)
b
C)
c
D)
d
E)
e
37)
A clear area against a confluent “lawn” of bacteria is called a
37)
A)
plaque.
B)
phage.
C)
rash.
D)
pock.
E)
cell lysis.
38)
A viral species is a group of viruses that
38)
A)
has the same genetic information and ecological niche.
B)
has the same morphology and nucleic acid.
C)
infects the same cells and cause the same disease.
D)
cannot be defined.
39)
Which of the following is necessary for replication of a prion?
39)
A)
RNA
B)
DNA
C)
lysozyme
D)
DNA polymerase
E)
PrPSc
40)
A virus’s ability to infect an animal cell depends primarily upon the
40)
A)
host cell’s ability to phagocytize viral particles.
B)
type of viral nucleic acid.
C)
enzymatic activity of a host cell.
D)
presence of receptor sites on the cell membrane.
E)
presence of pili on the host cell wall.
41)
Which of the following statements provides the most significant support for the idea that viruses
are nonliving chemicals?
41)
A)
They are chemically simple.
B)
They are not composed of cells.
C)
They cause diseases similar to those caused by chemicals.
D)
They are filterable.
E)
They cannot reproduce themselves outside a host.
42)
Which one of the following steps does NOT occur during multiplication of a picornavirus?
42)
A)
synthesis of – strands of RNA
B)
synthesis of + strands of RNA
C)
synthesis of viral proteins
D)
synthesis of DNA
E)
None of the answers is correct.
43)
The following steps occur during multiplication of herpesviruses. Which is the third step?
43)
A)
penetration
B)
attachment
C)
release
D)
uncoating
E)
biosynthesis
44)
Which of the following statements about viruses is FALSE?
44)
A)
Viruses contain a protein coat.
B)
Viruses contain DNA or RNA but never both.
C)
Viruses have genes.
D)
Viruses use their own catabolic enzymes.
E)
Viruses use the anabolic machinery of the cell.
45)
The most conclusive evidence that viruses cause cancers is provided by
45)
A)
cancer following injection of cell–free filtrates.
B)
finding oncogenes in viruses.
C)
some liver cancer patients having had hepatitis.
D)
treating cancer with antibodies.
E)
the presence of antibodies against viruses in cancer patients.
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
46)
Positive sense RNA strands of viruses are treated like mRNA inside the host cell.
46)
47)
Glycoprotein spikes are found on the capsids of all viruses.
47)
48)
A viroid is a completely developed infectious agent composed of nucleic acid and surrounded by a
capsid.
48)
49)
Viruses are the only known infectious agents that are obligatory intracellular parasites.
49)
50)
Dogs do not get measles because their cells lack the correct receptor sites for that virus.
50)
51)
A segmented genome can result in antigenic shift.
51)
52)
The basic mechanism of viral multiplication is similar for all viruses.
52)
53)
Binomial nomenclature is used to name viruses.
53)
54)
Most drugs that interfere with viral multiplication also interfere with host cell function.
54)
55)
Helical and icosahedral are terms used to describe the shapes of a virus envelope.
55)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
56)
Bacteriophages are used as vectors in genetic engineering to insert new genes into bacteria. Describe the process
that makes this genetic recombination possible.
57)
Compare and contrast the lytic cycle of infection of a DNA virus and an RNA virus.
58)
Discuss why viruses are considered infectious “particles” on the borderline between living and non–living.
59)
How is the replication of the viral genome of retroviruses unique among the viruses?
60)
Explain the steps involved in bacteriophage DNA entering a bacterial cell.
Answer Key
Testname: C13
Answer Key
Testname: C13