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Microbiology, 9e (Tortora)
Chapter 13
Objective Questions
1) In which of the following ways do viruses differ from bacteria?
A) Viruses are filterable.
B) Viruses are obligate intracellular parasites.
C) Viruses don't have any nucleic acid.
D) Viruses are not composed of cells.
E) All of the above.
2) Which of the following provides the most significant support for the idea that viruses are nonliving
chemicals?
A) They are not composed of cells.
B) They are filterable.
C) They cannot reproduce themselves outside of a host.
D) They cause diseases similar to those caused by chemicals.
E) They are chemically simple.
3) Which of the following is not true about spikes?
A) They are used for penetration.
B) They are used for absorption.
C) They may cause hemagglutination.
D) They are only found on enveloped viruses.
E) None of the above.
4) Which of the following is not used as a criterion to classify viruses?
A) Biochemical tests
B) Morphology
C) Nucleic acid
D) Size
E) Number of capsomeres
5) Which of the following is not a method of culturing viruses?
A) In laboratory animals
B) In culture media
C) In embryonated eggs
D) In cell culture
E) None of the above
Microbiology, 9e (Tortora)
Chapter 13
6) Bacteriophages and animal viruses do not differ significantly in which one of the following steps?
A) Adsorption
B) Penetration
C) Uncoating
D) Biosynthesis
E) Release
7) The definition of lysogeny is
A) Phage DNA is incorporated into host cell DNA.
B) Lysis of the host cell due to a phage.
C) The period during replication when virions are not present.
D) When the burst time takes an unusually long time.
E) None of the above.
8) A viroid is
A) A complete, infectious virus particle.
B) A naked, infectious piece of RNA.
C) A capsid without a nucleic acid.
D) A provirus.
E) None of the above.
Figure 13.1
9) In Figure 13.1, which of these is a complex virus?
A) a
B) b
C) c
D) d
E) All of the above
10) In Figure 13.1, the structures illustrated are composed of
A) DNA
B) RNA
C) DNA or RNA
D) Capsomeres
E) Capsids
Microbiology, 9e (Tortora)
Chapter 13
11) A clear area against a confluent "lawn" of bacteria is called a
A) Phage.
B) Pock.
C) Cell lysis.
D) Plaque.
E) None of the above.
12) Continuous cell lines differ from primary cell lines in that
A) Viruses can be grown in continuous cell lines.
B) Continuous cell lines always have to be reisolated from animal tissues.
C) Continuous cell lines are derived from primary cell lines.
D) Continuous cell lines can be maintained through an indefinite number of generations.
E) Continuous cell lines are from human embryos.
13) Which of the following is necessary for replication of a prion?
A) DNA
B) DNA polymerase
C) Lysozyme
D) PSc
E) RNA
14) A persistent infection is an infection in which
A) The virus remains in equilibrium with the host without causing a disease.
B) Viral replication is unusually slow.
C) The disease process occurs gradually over a long period.
D) Host cells are gradually lysed.
E) Host cells are transformed.
Microbiology, 9e (Tortora)
Chapter 13
15) Which of the following statements is not true?
A) A prophage is phage DNA inserted into a bacterial chromosome.
B) A prophage can pop out of the chromosome.
C) Prophage genes are represented by a repressor protein coded for by the prophage.
D) A prophage may result in new properties of the host cell.
E) The prophage makes the host cell immune to infection by other phages.
16) Lysogeny can result in all of the following except
A) Immunity to reinfection by the same phage.
B) Acquisition of new characteristics by the host cell.
C) Immunity to reinfection by any phage.
D) Transduction of specific genes.
E) None of the above.
17) Which of the following would be the first step in biosynthesis of a virus with a - strand of RNA?
A) Synthesis of DNA from an RNA template
B) Synthesis of double-stranded RNA from an RNA template
C) Synthesis of double-stranded RNA from a DNA template
D) Transcription of mRNA from DNA
E) None of the above
18) An infectious protein is a
A) Bacteriophage
B) Prion
C) Retrovirus
D) Viroid
E) None of the above
19) An envelope is acquired during which of the following steps?
A) Penetration
B) Adsorption
C) Uncoating
D) Release
E) None of the above
Microbiology, 9e (Tortora)
Chapter 13
20) Which of the following contributes to the difficulty in establishing the etiology of cancer?
A) Most viral particles can infect cells without inducing cancer.
B) Cancer may not develop until long after infection.
C) Cancers do not seem to be contagious.
D) Viruses are difficult to observe.
E) All of the above.
21) An example of a latent viral infection is
A) Subacute sclerosing panencephalitis.
B) Cold sores.
C) Influenza.
D) Smallpox.
E) None of the above.
22) The most common route of accidental AIDS transmission to health-care workers is
A) Mouth to mouth.
B) Fecal-oral.
C) Needlestick.
D) Aerosol.
E) Environmental surface contact.
23) Assume you have isolated an unknown virus. It is a single-stranded RNA, enveloped virus. To which group
does it most likely belong?
A) Herpesvirus
B) Picornavirus
C) Retrovirus
D) Togavirus
E) None of the above
24) To which group does a small, nonenveloped single-stranded RNA virus most likely belong?
A) Herpesvirus
B) Picornavirus
C) Retrovirus
D) Togavirus
E) None of the above
Microbiology, 9e (Tortora)
Chapter 13
25) The most conclusive evidence that viruses cause cancers is provided by
A) Finding oncogenes in viruses.
B) The presence of antibodies against viruses in cancer patients.
C) Cancer following injection of cell-free filtrates.
D) Treating cancer with antibodies.
E) Some liver cancer patients having had hepatitis.
26) Bacteriophages derive all of the following from the host cell except
A) Lysozyme.
B) tRNA.
C) Amino acids.
D) Nucleotides.
E) None of the above.
27) Generalized transduction differs from specialized transduction in that generalized transduction
A) Kills the host.
B) Transfers DNA from one cell to another.
C) Transfers specific DNA.
D) Involves lysogeny.
E) None of the above.
28) Generally, in a DNA-containing virus infection, the host animal cell supplies all of the following except
A) RNA polymerase.
B) Nucleotides.
C) DNA polymerase.
D) tRNA.
E) None of the above.
29) Put the following in the correct order for DNA-virus replication:
1-Maturation; 2-DNA synthesis; 3-Transcription; 4-Translation.
A) 1, 2, 3, 4
B) 2, 3, 4, 1
C) 3, 4, 1, 2
D) 4, 1, 2, 3
E) 4, 3, 2, 1
Microbiology, 9e (Tortora)
Chapter 13
30) A viral species is a group of viruses that
A) Have the same morphology and nucleic acid.
B) Have the same genetic information and ecological niche.
C) Infect the same cells and cause the same disease.
D) Can't be defined.
31) Viruses that have reverse transcriptase are in the
A) Retroviridae and Picornaviridae.
B) Herpesviridae and Retroviridae.
C) Hepadnaviridae and Retroviridae.
D) Bacteriophage families.
E) Influenzavirus.
32) DNA made from an RNA template will be incorporated into the virus capsid of
A) Retroviridae.
B) Herpesviridae.
C) Hepadnaviridae.
D) Bacteriophage families.
E) Influenzavirus.
33) Which of the following is not true about viruses?
A) Viruses contain DNA or RNA but never both.
B) Viruses contain a protein coat.
C) Viruses use the anabolic machinery of the cell.
D) Viruses use their own catabolic enzymes.
E) None of the above.
34) Approximately how many virus particles could fit along a 1 millimeter line?
A) 2
B) 20
C) 200
D) 20,000
E) 2,000,000
Microbiology, 9e (Tortora)
Chapter 13
35) Some viruses, such as Human Herpes Virus 1, infect a cell without causing symptoms; these are called
A) Latent viruses.
B) Lytic viruses.
C) Phages.
D) Slow viruses.
E) Unconventional viruses.
36) Latent viruses are present in cells as
A) Capsids.
B) Enzymes.
C) Prophages.
D) Proviruses.
E) None of the above.
37) Which one of the following steps does not occur during multiplication of a Rhabdovirus?
A) Synthesis of + strands of RNA
B) Synthesis of - strands of RNA
C) Synthesis of viral proteins
D) Synthesis of DNA
38) The following steps occur during multiplication of Herpesviruses. What is the third step?
A) Attachment
B) Biosynthesis
C) Penetration
D) Release
E) Uncoating
39) The following steps occur during multiplication of Retroviruses. What is the fourth step?
A) Synthesis of double-stranded DNA
B) Synthesis of + RNA
C) Attachment
D) Penetration
E) Uncoating
Microbiology, 9e (Tortora)
Chapter 13
40) Nontoxic strains of Vibrio cholerae can become toxic when they are in the human intestine with toxic strains of
bacteria. This suggests that the toxin genes are acquired by
A) Host enzymes.
B) Prions.
C) Reverse transcriptase.
D) Transduction.
E) None of the above.
41) Which one of the following steps does not occur during multiplication of a Picornavirus?
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 above
42) An oncogenic RNA virus must have which of the following enzymes?
A) DNA-dependent DNA polymerase
B) Lysozyme
C) RNA polymerase
D) Reverse transcriptase
E) All of the above
Answer: D
Skill: Understanding
43) Which of the following is most likely a product of an early gene?
A) Capsid proteins
B) DNA polymerase
C) Envelope proteins
D) Spike proteins
E) Lysozyme
44) Most RNA viruses carry which of the following enzymes?
A) DNA-dependent DNA polymerase
B) Lysozyme
C) RNA-dependent RNA polymerase
D) Reverse transcriptase
E) ATP synthase
Microbiology, 9e (Tortora)
Chapter 13
45) The following steps occur during biosynthesis of a + strand RNA virus. What is the third step?
A) Attachment
B) Penetration and uncoating
C) Synthesis of - strand RNA
D) Synthesis of + strand RNA
E) Synthesis of viral proteins