MICROBIOLOGY CHAPTER 13

56) How do all viruses differ from bacteria?
A) Viruses are filterable.
B) Viruses do not have any nucleic acid.
C) Viruses are obligate intracellular parasites.
D) Viruses do not reproduce.
E) Viruses are not composed of cells.

57) Which of the following statements provides the most significant support for the idea that viruses are nonliving chemicals?
A) They cannot reproduce themselves outside a host.
B) They cause diseases similar to those caused by chemicals.
C) They are not composed of cells.
D) They are chemically simple.
E) They are filterable.

58) Which of the following statements about viral spikes is FALSE?
A) They are used for attachment.
B) They bind to receptors on the host cell surface.
C) They are composed of carbohydrate-protein complexes.
D) They are found only on nonenveloped viruses.
E) They may cause hemagglutination.

59) Which of the following is NOT used as a criterion to classify viruses?
A) morphology
B) nucleic acid
C) biochemical tests
D) size
E) number of capsomeres

60) Which of the following is NOT utilized to culture viruses?
A) animal cell cultures
B) culture media
C) embryonated eggs
D) bacterial cultures
E) laboratory animals

61) Bacteriophages and animal viruses do NOT differ significantly in which one of the following steps?
A) biosynthesis
B) attachment
C) penetration
D) uncoating
E) release

62) The definition of lysogeny is
A) attachment of a phage to a cell.
B) the period during replication when virions are not present.
C) phage DNA is incorporated into host cell DNA.
D) lysis of the host cell due to a phage.
E) when the burst time takes an unusually long time.

64) The structures illustrated in Figure 13.1 are composed of
A) DNA or RNA.
B) RNA.
C) Capsomeres.
D) DNA.
E) viroids.

65) A clear area against a confluent "lawn" of bacteria is called a
A) cell lysis.
B) pock.
C) rash.
D) phage.
E) plaque.

66) A persistent infection is one in which
A) viral replication is unusually slow.
B) host cells are gradually lysed.
C) the disease process occurs gradually over a long period.
D) host cells are transformed.
E) the virus remains in equilibrium with the host without causing a disease.

67) Which of the following statements is FALSE?
A) A prophage is phage DNA inserted into a bacterial chromosome.
B) A prophage may result in new properties of the host cell.
C) Prophage genes are repressed by a repressor protein coded for by the prophage.
D) A prophage can "pop" out of the chromosome.
E) The prophage makes the host cell immune to infection by other phages.

68) Lysogeny can result in all of the following EXCEPT
A) acquisition of new characteristics by the host cell.
B) immunity to reinfection by any phage.
C) immunity to reinfection by the same phage.
D) specialized transduction.
E) phage conversion.

69) An infectious protein is a
A) papovavirus.
B) bacteriophage.
C) viroid.
D) retrovirus.
E) prion.

70) An envelope is acquired during which of the following steps?
A) adsorption
B) release
C) penetration
D) biosynthesis
E) uncoating

71) Which of the following statements is NOT true of lysogeny?
A) It causes lysis of host cells.
B) It is a "silent" infection; the virus does not replicate.
C) Prophage is inserted into the host genome.
D) It can give infected pathogens the genetic information for toxin production.
E) Lytic cycle may follow lysogeny.

72) An example of a latent viral infection is
A) cold sores.
B) subacute sclerosing panencephalitis.
C) influenza.
D) smallpox.
E) mumps.

73) A virus's ability to infect an animal cell depends primarily upon the
A) presence of receptor sites on the cell membrane.
B) enzymatic activity of a host cell.
C) host cell's ability to phagocytize viral particles.
D) presence of pili on the host cell wall.
E) type of viral nucleic acid.

74) The mechanism whereby an enveloped virus leaves a host cell is called
A) penetration.
B) budding.
C) lysogeny.
D) abduction.
E) transduction.

75) The most conclusive evidence that viruses cause cancers is provided by
A) the presence of antibodies against viruses in cancer patients.
B) finding oncogenes in viruses.
C) cancer following injection of cell-free filtrates.
D) some liver cancer patients have hepatitis.
E) treating cancer with antibodies.

76) Bacteriophages derive all of the following from the host cell EXCEPT
A) tRNA.
B) ATP.
C) nucleotides.
D) amino acids.
E) lysozyme.