Micro Chapter 5 – Flashcards
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Viruses a. cannot be seen in a light microscope. b. are prokaryotic. c. contain 70S ribosomes. d. undergo binary fission. e. All of the choices are correct.
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a
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A naked virus only has a(n) a. capsid. b. capsomere. c. nucleocapsid. d. envelope. e. antigenic surface.
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c
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Which of the following is incorrect about prophages? a. present when the virus is in lysogeny b. formed when viral DNA enters the bacterial chromosome c. replicated with host DNA and passed on to progeny d. cause lysis of host cells e. occur when temperate phages enter host cells
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d
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All of the following pertain to virus envelopes except a. gained as a virus leaves the host cell membrane. b. are comprised primarily of lipids. c. contain special virus proteins. d. help the virus particle attach to host cells. e. are located between the capsid and nucleic acid.
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e
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Uncoating of viral nucleic acid a. does not occur in bacteriophage multiplication. b. involves enzymatic destruction of the capsid. c. releases viral nucleic acid into the cell. d. occurs before replication. e. All of the choices are correct.
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e
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Host cells of viruses include a. humans and other animals. b. plants and fungi. c. bacteria. d. protozoa and algae. e. All of the choices are correct.
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e
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Viruses with _____ -sense RNA contain the correct message for translation, while viruses with _____ -sense RNA must first be converted into a correct message. a. positive, negative b. negative, positive c. primary, secondary d. secondary, primary e. None of the choices is correct.
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a
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Which of the following will not support viral cultivation? a. live lab animals b. embryonated bird eggs c. primary cell cultures d. continuous cell cultures e. All of the choices will support viral cultivation.
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e
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Which of the following is not associated with every virus? a. envelope b. capsomeres c. capsid d. nucleic acid e. genome
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a
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Cells grown in culture form a(n) a. monolayer. b. bilayer. c. aggregate. d. plaque. e. None of the choices is correct.
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a
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Who developed a rabies vaccine by separating bacteria from virus using a filter? a. Leewonhoek b. Koch c. Pasteur d. Cohn e. Semmelwise
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c
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Viruses that infect bacteria are specifically called a. viroids. b. prions. c. bacteriophages. d. satellite viruses. e. All of the choices infect bacteria.
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c
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Which of the following is not a typical capsid shape? a. tetrahedral b. complex c. helical d. icosahedron e. All of the choices are capsid shapes.
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a
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Which of the following occurs during assembly? a. Nucleocapsid is formed. b. New viral nucleic acid is formed. c. Viral spikes insert in host cell membrane. d. A nucleocapsid is formed and viral spikes insert in host cell membrane. e. All of the choices occur.
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d
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Two noncellular agents, smaller than viruses, are the infectious proteins called _____ and the infectious RNA strands called _____. a. prions, capsomeres b. virions, prions c. viroids, phages d. prions, phages e. prions, viroids
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e
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Virus capsids are made from subunits called a. envelopes. b. spikes. c. capsomeres. d. prophages. e. peplomers.
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c
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A(n) _____ is the protein shell around the nucleic acid core of a virus. a. capsomere b. capsid c. spike d. envelope e. monolayer
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b
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A negative-sense RNA virus a. is ready for immediate translation. b. must synthesize a negative RNA copy of its genome. c. must synthesize a positive RNA copy of its genome. d. is a special form of tRNA used by viruses. e. always codes for RNA polymerase.
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c
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Infectious naked strands of RNA that affect plants are called a. viroids. b. phages. c. prions. d. oncogenic viruses. e. spikes.
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a
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Satellite viruses are a. also called viroids. b. dependent on other viruses for replication. c. the cause of spongiform encephalopathies. d. significant pathogens of plants. e. All of the choices are correct.
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b
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Oncoviruses include all the following except a. hepatitis B virus. b. measles virus. c. papillomavirus. d. HTLV I. e. Epstein-Barr virus.
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b
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Viruses acquire envelopes around their nucleocapsids during a. replication. b. assembly. c. adsorption. d. release. e. penetration.
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d
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The process of dissolving the envelope and capsid to release the viral nucleic acid is a. adsorption. b. penetration. c. uncoating. d. synthesis. e. assembly.
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c
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Reverse transcriptase synthesizes a. the positive RNA strand from a negative RNA strand. b. a negative RNA strand from a positive RNA strand. c. RNA from DNA. d. DNA from RNA. e. None of the choices is correct.
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d
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One of the principal capsid shapes is a 20-sided figure with 12 evenly spaced corners referred to as a(n) _____ capsid. a. spiked b. complex c. icosahedral d. helical e. buckeyball
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c
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A common method for cultivating viruses in the lab is to use in vitro systems called _____ cultures. a. embryo b. cell c. plaque d. bacteriophage e. egg
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b
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When a bacterium acquires a trait from its temperate phage, it is called a. transformation. b. lysogenic conversion. c. viral persistence. d. transcription. e. translation.
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b
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Helical and icosahedral are terms used to describe the shapes of a virus a. spike. b. capsomere. c. envelope. d. capsid. e. core.
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d
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Persistent viruses that can reactivate periodically are a. chronic latent viruses. b. oncoviruses. c. syncytia. d. inclusion bodies. e. cytopathic.
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a
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Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called a. latent. b. oncogenic. c. prions. d. viroids. e. delta agents.
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a
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The primary purpose of viral cultivation is a. to isolate and identify viruses in clinical specimens. b. to prepare viruses for vaccines. c. to do detailed research on viral structure, lifestyle, genetics, and effects on host cells. d. All of the choices are correct.
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d
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The activation of a prophage is called a. activation. b. lysogeny. c. transformation. d. induction. e. adsorption.
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d
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What structures are used by bacteriophages to attach to host cell receptors? a. sheath b. tail fibers c. nucleic acid d. capsid head e. None of the choices is correct.
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b
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Infectious protein particles are called a. viroids. b. phages. c. prions. d. oncogenic viruses. e. spikes.
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c
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Viruses attach to their hosts via a. host glycoproteins. b. host phospholipids. c. viral phospholipids. d. viral flagella. e. All of the choices are correct.
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a
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Lysogeny refers to a. altering the host range of a virus. b. latent state of herpes infections. c. virion exiting host cell. d. viral genome inserting into bacterial host chromosome. e. None of the choices is correct.
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d
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Which of the following is not a characteristic of a transformed cell? a. viral nucleic acid integrated into host DNA b. decreased growth rate c. alterations in chromosomes d. changes in cell surface molecules e. capacity to divide indefinitely
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b
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Reverse transcriptase synthesizes a. the positive RNA strand from a negative RNA strand. b. a negative RNA strand from a positive RNA strand. c. RNA from DNA. d. DNA from RNA. e. None of the choices is correct.
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d
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Which of the following is a type of cytopathic effect? a. inclusions in the nucleus b. multinucleated giant cells c. inclusions in the cytoplasm d. cells change shape e. All of the choices are correct.
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e
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Mammalian viruses capable of starting tumors are a. chronic latent viruses. b. oncoviruses. c. syncytia. d. inclusion bodies. e. cytiopathic.
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b
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Host range is limited by a. type of nucleic acid in the virus. b. age of the host cell. c. type of host cell receptors on cell membrane. d. size of the host cell. e. All of the choices are correct.
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c
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What type of phage enters an inactive prophage stage? a. primary b. secondary c. temperate d. temporary e. transformed
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c
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The event that occurs in bacteriophage multiplication that does not occur in animal virus replication is a. adsorption to the host cells. b. injection of only the viral nucleic acid into the host cell. c. host cell synthesis of viral enzymes and capsid proteins. d. assembly of nucleocapsids. e. replication of viral nucleic acid.
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b
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In general, most DNA viruses multiply in the host cell's _____, while most RNA viruses multiply in the host cell's _____. a. nucleus, cytoplasm b. cytoplasm, cell membrane c. cell membrane, cytoplasm d. cytoplasm, nucleus e. nucleus, endoplasmic reticulum
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a
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The core of every virus particle always contains a. DNA. b. capsomeres. c. enzymes. d. DNA and RNA. e. either DNA or RNA
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e
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Viral nucleic acids include which of the following? a. double-stranded DNA b. single-stranded DNA c. double-stranded RNA d. single-stranded RNA e. All of the choices are correct.
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e
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During lysogeny, an inactive prophage state occurs when the viral DNA is inserted into the da. host cytoplasm. b. host nucleus. c. host nucleolus. d. host DNA. e. host cell membrane.
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d
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Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called a. lysogeny. b. budding. c. plaques. d. cytopathic effects. e. pocks.
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c
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T-even phages a. include the poxviruses. b. infect Esherichia coli cells. c. enter host cells by engulfment. d. have helical capsids. e. All of the choices are correct.
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b
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The envelope of enveloped viruses is a. identical to the host plasma membrane. b. only composed of host endomembrane. c. always includes spikes. d. is obtained by viral budding or exocytosis. e. None of the choices is correct.
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d
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Viruses have all the following except a. definite shape. b. metabolism. c. genes. d. the ability to infect host cells. e. ultramicroscopic size.
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b
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Creutzfeld-Jacob disease is a. caused by a chronic latent virus. b. initiated by an oncogenic virus. c. caused by a viroid. d. a spongiform encephalopathy of humans. e. also called "mad cow disease."
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d
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New, nonenveloped virus release occurs by a. lysis. b. budding. c. exocytosis. d. both lysis and budding. e. both budding and exocytosis.
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a
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The development of antiviral drug therapy is difficult because a. viruses are obligate intracellular parasites so the host cell can be harmed by the drug. b. viruses do not have specific replication cycles that can be targeted. c. viruses do not contain genetic material. d. their life cycles do not have distinctive stages.
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a
