Chapter 13 Viruses Flashcards
The term filterable viruses was coined by
A. Beijerinck.
B. Iwanowsky.
C. Twort.
D. d’Herelle.
A. Beijerinck.
Crystallization of Tobacco Mosaic Virus was accomplished by
A. Berkley.
B. Stanley.
C. Iwanowsky.
D. Twort.
B. Stanley.
Viruses that infect bacteria are referred to as
A. viralcidens.
B. bacteriocidins.
C. bacterialogens.
D. bacteriophages.
D. bacteriophages.
A virion is a(n)
A. pathogenic virus.
B. subviral particle.
C. complete, extracellular virus particle.
D. enveloped virus particle.
C. complete, extracellular virus particle.
A virion is composed of
A. lipid, protein, and either RNA or DNA.
B. protein and either RNA or DNA.
C. protein and both, RNA and DNA.
D. protein, either RNA or DNA, and possibly lipid.
D. protein, either RNA or DNA, and possibly lipid.
The protein coat of a virus
A. is called a capsomere.
B. is called a capsid.
C. protects the nucleic acid.
D. is involved in recognition of host cell receptors.
E. is called a capsid, protects the nucleic acid AND is involved in recognition of host cell receptors.
E. is called a capsid, protects the nucleic acid AND is involved in recognition of host cell receptors.
Which does not refer to the shape of a virus?
A. icosahedral (isometric)
B. helical
C. complex
D. bacillus
D. bacillus
The shape of the virus is determined by its
A. nucleic acid.
B. capsid.
C. envelope.
D. tail.
B. capsid.
The viral envelope closely resembles the
A. prokaryotic cell wall.
B. capsomere.
C. eukaryotic cell membrane.
D. cytoplasm.
C. eukaryotic cell membrane.
The protein projections on the surface of a virus that are involved in attachment to the host cell are called
A. suckers.
B. pili.
C. cilia.
D. spikes.
E. hooks.
D. spikes.
Outside of living cells, viruses are
A. scavenging glucose.
B. slowly stockpiling ATP from the mitochondria.
C. using cilia to move to the next host.
D. metabolically inert.
D. metabolically inert.
Viruses
A. probably keep the numbers of bacteria in check.
B. have no effect on the number of bacteria.
C. increase the number of bacteria.
D. are active in passing DNA from one bacterium to another.
E. probably keep the numbers of bacteria in check AND are active in passing DNA from one bacterium to another.
E. probably keep the numbers of bacteria in check AND are active in passing DNA from one bacterium to another.
What part of the attached bacteriophage enters through the host cell wall?
A. the entire virus
B. only the enzymes necessary for replication
C. the nucleic acid
D. the nucleic acid and capsid
E. the capsid only
C. the nucleic acid
A phage that replicates inside the host cell and then lyses its host during its release is a
A. virulent or lytic phage.
B. latent phage.
C. lysogenic phage.
D. dormant phage.
A. virulent or lytic phage.
The correct order for the stages of a phage infection is:
A. penetration, transcription, attachment, replication of nucleic acid and protein, assembly, release
B. attachment, penetration, transcription, replication of nucleic acid and protein, assembly, release
C. attachment, replication of nucleic acid and protein, penetration, transcription, assembly, release
D. transcription, attachment replication of nucleic acid and protein, assembly, penetration, release
B. attachment, penetration, transcription, replication of nucleic acid and protein, assembly, release
Phages that can either replicate and cause cell lysis or can integrate their DNA into the host DNA are called
A. lysogenic phages.
B. lytic phages.
C. virulent phages.
D. segmented phages.
A. lysogenic phages.
One of the most intensively studied virulent phages which infects E. coli is
A. T9.
B. T4.
C. beta.
D. gamma.
B. T4.
During attachment of phage to E. coli, the phage
A. actively seek out the bacteria.
B. randomly bump into the bacteria.
C. attach to proteins or carbohydrates on the bacterial surface.
D. attach to the bacterial RNA.
E. randomly bump into the bacteria AND attach to proteins or carbohydrates on the bacterial surface.
E. randomly bump into the bacteria AND attach to proteins or carbohydrates on the bacterial surface.
What part of the E. coli T4 phage attaches to the host cell receptors?
A. Capsid fragments around the nucleic acid.
B. Protein fibers at the end of the phage tail.
C. Pili of the envelope.
D. Spikes of the envelope.
B. Protein fibers at the end of the phage tail.
During penetration of E. coli by the T4 phage
A. lysozyme is used to allow entry of the phage capsid.
B. the tail acts as a “hypodermic needle”, injecting the phage DNA into the cell.
C. the protein fibers digest a hole in the cell wall.
D. the bacterial receptor molecules open a hole through the cell wall.
B. the tail acts as a “hypodermic needle”, injecting the phage DNA into the cell.
Phage-encoded proteins are
A. coded for by host DNA.
B. coded for by phage DNA.
C. proteins normally present in the uninfected cell.
D. early proteins.
E. coded for by phage DNA AND early proteins.
E. coded for by phage DNA AND early proteins.
Phage-encoded enzymes are
A. all produced simultaneously.
B. produced in a sequential manner.
C. strictly host enzymes.
D. used to customize the cell for viral production.
E. produced in a sequential manner AND used to customize the cell for viral production.
E. produced in a sequential manner AND used to customize the cell for viral production.
Assembly of the T4 phage
A. may involve some self-assembly.
B. may involve the use of scaffolds.
C. is completely self-assembly.
D. is completely dependent on scaffolds.
E. may involve some self-assembly AND may involve the use of scaffolds.
E. may involve some self-assembly AND may involve the use of scaffolds.
In the case of T-even phages, the burst size is about
A. 1 per host cell.
B. 5 per host cell.
C. 200 per host cell.
D. 1000 per host cell.
C. 200 per host cell.
The time from absorption to release for T-even phage is about
A. 1 minute.
B. 10 minutes.
C. 30 minutes.
D. 1 day.
C. 30 minutes.
The replicative form of nucleic acid in filamentous phages is
A. dsDNA.
B. dsRNA.
C. positive ssRNA.
D. negative ssDNA.
A. dsDNA.
Filamentous phage
A. only infect E. coli that have pili.
B. only infect E. coli lacking pili.
C. infect E. coli regardless of the presence of pili.
D. do not infect E. coli.
A. only infect E. coli that have pili.
Which is a filamentous phage?
A. M13
B. T4
C. lambda
D. phi X174
A. M13
The bacterial viruses that are released by a process termed extrusion are called
A. lysogenic viruses.
B. temperate phages.
C. filamentous phages.
D. lambda viruses.
C. filamentous phages.
The filamentous phages all contain
A. single-stranded DNA.
B. double-stranded DNA.
C. single-stranded RNA.
D. double-stranded RNA.
A. single-stranded DNA.
Bacteria infected with filamentous phages are termed
A. temperate cells.
B. plaque-producing cells.
C. virulent strains.
D. carrier cells.
D. carrier cells.
An exit method used by viruses which does not immediately destroy the host bacterium is
A. lysis.
B. inversion.
C. extrusion.
D. excising.
C. extrusion.
In the replication of phage containing positive-sense DNA,
A. the host’s enzymes are used to make dsDNA.
B. the host’s DNA polymerase uses the phage RNA as a template to make negative-sense DNA.
C. a phage-encoded DNA polymerase is used to make negative-sense RNA using the phage positive-sense RNA as a template.
D. a phage-encoded DNA polymerase is used to make DNA using the phage positive-sense RNA as a template.
A. the host’s enzymes are used to make dsDNA.
Most phages that contain single-stranded DNA
A. are extruded.
B. contain a positive-sense DNA strand.
C. have their DNA transformed to double-stranded DNA before replication and transcription occur.
D. All of the choices are correct.
D. All of the choices are correct.
RNA phages usually contain
A. dsRNA.
B. dsDNA.
C. ssRNA.
D. ssDNA.
C. ssRNA.
Regarding phage replication,
A. the majority of phages are temperate.
B. when integrated into host DNA, the phage DNA is called a prophage.
C. lambda is a good example of a temperate phage.
D. All of the choices are correct.
D. All of the choices are correct
A temperate phage
A. may be lysogenic.
B. may be lytic.
C. enters a lysogenic or lytic life cycle shortly after entering the host cell.
D. are all RNA viruses.
E. may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell.
E. may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell.
The integration of phage DNA into the bacterial chromosome occurs because of
A. identical DNA sequences in both.
B. the phage’s ability to synthesize enzymes to enter the bacterium.
C. similar RNA nucleotides in both.
D. the similarity in enzyme metabolism.
E. the phage’s ability to synthesize enzymes to enter the bacterium AND similar RNA nucleotides in both.
A. identical DNA sequences in both.
Once integrated, phage DNA can remain in the prophage state as long as
A. the bacteria is frequently plated on new media.
B. certain phage genes are excised.
C. certain phage genes are repressed.
D. bacterial repressor genes are activated.
C. certain phage genes are repressed.
The activation of the SOS system in a bacterium infected with a prophage results in
A. destruction of the viral genes.
B. complete lysis of the bacterial culture.
C. mutation of the DNA.
D. destruction of the viral repressor through host protease activity.
E. complete lysis of the bacterial culture AND destruction of the viral repressor through host protease activity.
E. complete lysis of the bacterial culture AND destruction of the viral repressor through host protease activity.
Lysogenized cells
A. are immune to any further infection by any virus.
B. are immune to infection by the same virus.
C. may have new properties.
D. respond to infection with the SOS response.
E. are immune to infection by the same virus AND may have new properties.
E. are immune to infection by the same virus AND may have new properties.
The phenomenon responsible for the ability of Corynebacterium diphtherium to produce the virulent toxin responsible for the devastating effects of diphtheria is called
A. self-assembly.
B. matrix conversion.
C. prion protein.
D. lysogenic conversion.
D. lysogenic conversion.
Transducing virulent phages do not lyse the cells they invade because
A. transformation is taking place in the phage and this is transferred to the bacterium.
B. bacterial DNA has replaced critical viral DNA in the phage.
C. their virulence is dependent on the bacteria and virus replicating together.
D. the lytic genes are unable to enter during penetration and are shed outside the host.
B. bacterial DNA has replaced critical viral DNA in the phage.
DNA is protected from restriction enzymes by being
A. sequestered in a lysosome.
B. turned into RNA.
C. methylated.
D. made into double stranded RNA.
C. methylated.
A limiting factor for viral infection is
A. internal metabolic temperature of the host cell.
B. nutrition of the host cell.
C. stage of cell cycle of the host cell.
D. presence of specific receptor molecules on the host cell.
D. presence of specific receptor molecules on the host cell.
If the infecting phage lacks some critical pieces of DNA necessary for replication it is called
A. incomplete.
B. mutated.
C. defective.
D. vegetative.
C. defective.
Specialized transduction
A. involves the random transmission of any gene.
B. involves the transfer of a few specific genes.
C. utilizes a defective virus.
D. only involves genes near the viral DNA integration site.
E. involves the transfer of a few specific genes, utilizes a defective virus AND only involves genes near the viral DNA integration site.
E. involves the transfer of a few specific genes, utilizes a defective virus AND only involves genes near the viral DNA integration site.
Once inside the host cell, phage DNA
A. is replicated.
B. is transcribed.
C. may get degraded by bacterial nucleases.
D. All of the choices are correct.
D. All of the choices are correct.
Using phages to treat a bacterial infection is an interesting idea because
A. a single type of phage can destroy a wide range of strains of the same pathogen.
B. of the increasing problem of antibiotic resistance.
C. lysed bacteria pose no threat.
D. a single phage can be genetically engineered to infect many different species of bacteria.
B. of the increasing problem of antibiotic resistance.
The RNA phages contain only a single positive-sense strand of RNA.
TRUE
A lysogenic cell contains viral DNA, a prophage, integrated into the host chromosome.
TRUE
The integration of phage DNA into host DNA occurs in much the same fashion as seen in transformation, transduction or conjugation.
TRUE
Filamentous virus is incapable of causing a lytic infection
TRUE
Completed filamentous phages are often found in the cytoplasm of infected bacteria.
FALSE