MICROBIOLOGY 5
What are the 5 properties of viruses ?
1.)Can be DNA or RNA cannot be both 2.)Unable to multiple independently without a host cell 3.)Lack Enzymes for metabolic processes 4.)Lack machinery for synthesizing proteins 5.)Can be double stranded RNA or DNA and Single stranded RNA or DNA
10) 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.
A
14) Which of the following is not associated with every virus? A) Envelope B) Capsomeres C) Capsid D) Nucleic acid E) Genome
A
18) 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 are correct
A
20) 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
A
25) 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
A
30) Persistent viruses that can reactivate periodically are ________. A) chronic latent viruses B) oncoviruses C) syncytia D) inclusion bodies E) cytopathic
A
32) New, nonenveloped virus release occurs by ________. A) lysis B) budding C) exocytosis D) both lysis and budding E) both budding and exocytosis
A
37) 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
A
4) 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
A
47) Cells grown in culture form a(n) ________. A) monolayer B) bilayer C) aggregate D) plaque E) None of the choices are correct
A
50) Infectious naked strands of RNA that affect plants are called ________. A) viroids B) phages C) prions D) oncogenic viruses E) spikes
A
54) 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
A
75) Viral genetic studies, vaccine development and clinical identification would not be possible without the ability to ________. A) culture viruses in vivo and in vitro B) transform human cells into cancerous cells C) studying prions in neurological tissue of animals D) activate lysogenic induction in bacteriophages
A
77) An ideal antiviral drug would be one that ________. A) disrupted an integral viral process while causing little damage to the host cell B) killed the host cell thereby depriving the virus of its means to translate proteins C) killed both the virus and the host cell D) prevents translation by the host cell ribosome, depriving the virus of a means to replicate
A
VIVO is
Animals and embryo
1) Viruses have all the following except ________. A) definite shape B) metabolism C) genes D) the ability to infect host cells E) ultramicroscopic size
B
12) Viral spikes ________. A) are present on all viruses B) protrude from the envelope C) block attachment between virus and host D) are derived from host proteins E) All of the choices are correct
B
22) Oncoviruses include all the following except ________. A) hepatitis B virus B) measles virus C) papillomavirus D) HTLV I E) Epstein-Barr virus
B
29) Mammalian viruses capable of starting tumors are ________. A) chronic latent viruses B) oncoviruses C) syncytia D) inclusion bodies E) cytopathic
B
31) 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
B
33) 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 are correct
B
36) 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
B
44) 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
B
48) 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
B
52) 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
B
7) A(n) ________ is the protein shell around the nucleic acid core of a virus. A) capsomere B) capsid C) spike D) envelope E) monolayer
B
17) 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
C
2) Who developed a rabies vaccine by separating bacteria from virus using a filter? A) Leeuwenhoek B) Koch C) Pasteur D) Cohn E) Semmelwise
C
21) 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
C
27) 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
C
40) Viruses that infect bacteria are specifically called ________. A) viroids B) prions C) bacteriophages D) satellite viruses E) All of the choices infect bacteria.
C
42) What type of phage enters an inactive prophage stage? A) Primary B) Secondary C) Temperate D) Temporary E) Transformed
C
46) 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
C
49) Infectious protein particles are called ________. A) viroids B) phages C) prions D) oncogenic viruses E) spikes
C
5) Virus capsids are made from subunits called ________. A) envelopes B) spikes C) capsomeres D) prophages E) peplomers
C
8) 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
C
9) A naked virus has only a(n) ________. A) capsid B) capsomere C) nucleocapsid D) envelope E) antigenic surface
C
Vitro is ?
Cells and tissue
16) 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 are correct
D
19) Viruses acquire envelopes around their nucleocapsids during ________. A) replication B) assembly C) adsorption D) release E) penetration
D
24) The envelope of enveloped viruses ________. A) is identical to the host plasma membrane B) is only composed of host endomembrane C) does not contain spikes D) is obtained by viral budding or exocytosis E) None of the choices are correct
D
26) Viral tissue specificities are called ________. A) ranges B) virions C) receptacles D) tropisms E) uncoating
D
28) Which of the following occurs during assembly of an enveloped virus? 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.
D
34) 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
D
39) 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 are correct
D
41) During lysogeny, an inactive prophage state occurs when the viral DNA is inserted into the ________. A) host cytoplasm B) host nucleus C) host nucleolus D) host DNA E) host cell membrane
D
43) The activation of a prophage is called ________. A) activation B) lysogeny C) transformation D) induction E) adsorption
D
51) Creutzfeldt-Jakob 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"
D
55) 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
D
6) Helical and icosahedral are terms used to describe the shapes of a virus ________. A) spike B) capsomere C) envelope D) capsid E) core
D
11) 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
E
13) The core of every virus particle always contains ________. A) DNA B) capsomeres C) enzymes D) DNA and RNA E) either DNA or RNA
E
15) 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
E
23) 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
E
3) 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
E
38) 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
E
45) 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
E
53) 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
E
58) Viruses are ultramicroscopic because they range in size from 2 mm to 450 mm.
FALSE
61) A specific animal virus has the ability to attach to and enter almost any animal host cell
FALSE
65) The adeno-associated virus (AAV) is a prion.
FALSE
68) Viruses are not filterable
FALSE
72) Glycoprotein spikes are essential for mediating the release stage of the viral life cycle.
FALSE
78) An ideal antiviral drug would be one that killed the host cell, effectively preventing the virus from replicating.
FALSE
ADSORPTION IS
Specific attachment proteins on the surface of viruses bind to specific receptors on the surface of animal cells.
56) When a virus enters a host cell, the viral genes redirect the genetic and metabolic activities of the host cell.
TRUE
57) Viruses are used to produce vaccines for prevention of certain viral infections.
TRUE
59) A fully formed virus that can cause an infection in a host cell is called a virion.
TRUE
60) Spikes are glycoproteins of the virus capsid.
TRUE
62) Viral spikes are inserted into the host cell membrane before budding or exocytosis.
TRUE
63) Prophages can be activated into viral replication and enter the lytic cycle.
TRUE
64) Viruses are the most common cause of acute infections that do not result in hospitalization.
TRUE
66) Viruses are simple, noncellular, and lack ribosomes.
TRUE
67) Viruses mutate and some have not been discovered.
TRUE
69) Viruses are unable to multiply outside of a host cell.
TRUE
76) It is necessary to culture viruses both in vivo and in vitro so that vaccines can be developed, analysis of viral genomes can be made and viruses in clinical specimens can be identified.
TRUE
Uncoating
the viral nucleic acid is released from the capsid during or after penetration
Penetration is
the virus, or at least its nucleic acid, must enter the cell. Animal viruses do this primarily by one of two mechanisms.
Release
•Assembled viruses leave their host in one of two ways: •Nonenveloped and complex viruses that reach maturation in the cell nucleus or cytoplasm are released when the cell lyses or rupture •Enveloped viruses are liberated by budding from the membranes of the cytoplasm, nucleus, endoplasmic reticulum, or vesicles
Assembly
•Mature virus particles are constructed from the growing pool of parts •Capsid is first laid down as an empty shell that will serve as a receptacle for the nucleic acid strand
Synthesis
•Viral nucleic acid begins to synthesize the building blocks for new viruses