ch 18 - Chapter 18: The Genetics of Viruses and Bacteria...

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Chapter 18: The Genetics of Viruses and Bacteria MULTIPLE CHOICE 1) Which of the following is (are) true about viruses? A) Viruses are classified below the cellular level of biological organization. B) A single virus particle contains both DNA and RNA. C) Even small virus particles are visible with light microscopes. D) Only A and B are true. E) A, B, and C are true. ANS: A PTS: 1 TOP: Concept 18.1 2) Which of the following is not a reason scientists suspected that something other than bacteria was the cause of tobacco mosaic disease? A) Passing infectious sap through a fine filter failed to remove the infectious agent. B) Treating infectious sap with alcohol failed to remove the infectious agent. C) No cells could be seen in the infectious sap using a light microscope. D) The infectious agent in the sap could reproduce, as its ability to cause disease was undiluted even after many transfers from plant to plant. E) The infectious agent could not be cultivated on nutrient media in petri dishes or in test tubes. ANS: D PTS: 1 TOP: Concept 18.1 3) 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. ANS: C PTS: 1 TOP: Concept 18.1 4) Which of the following is a characteristic of all viruses? A) a nucleic acid genome B) a protein capsid C) a viral envelope D) A and B only E) A, B, and C ANS: D PTS: 1 TOP: Concept 18.1 5) Viral genomes can consist of any of the following except A) double-stranded DNA. B) double-stranded RNA. C) single-stranded DNA. D) single-stranded RNA. E) helical capsomeres. ANS: E PTS: 1 TOP: Concept 18.1
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6) The host range of a virus is determined by A) the proteins on its surface. B) whether its nucleic acid is DNA or RNA. C) the proteins on the surface of the host cell. D) the enzymes produced by the virus before it infects the cell. E) both A and C ANS: E PTS: 1 TOP: Concept 18.1 7) Viruses are referred to as obligate parasites because A) they cannot reproduce outside of a host cell. B) viral DNA always inserts itself into host DNA. C) they invariably kill any cell they infect. D) they can incorporate nucleic acids from other viruses. E) they must use enzymes encoded by the virus itself. ANS: A
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This note was uploaded on 05/01/2008 for the course BIO 320 taught by Professor Walsh,weinert during the Spring '07 term at University of Arizona- Tucson.

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ch 18 - Chapter 18: The Genetics of Viruses and Bacteria...

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