Chap 6 TB
Cells grown in culture form a/an ______. A. monolayer B. bilayer C. aggregate D. plaque
A
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
In order to replicate within a host cell, a virus with a genome comprised of single-stranded positive-sense RNA A. must use its genomic strand as a template to make copies of negative-sense RNA for packaging. B. must use its genomic strand as a template to make copies of positive-sense RNA for packaging. C.must first use its genomic strand as a template to make a negative-sense RNA, which then serves as a template to synthesize positive-sense RNA for packaging. D. must first use its genomic strand as a template to make copies of DNA for packaging
A
Infectious naked strands of RNA that affect plants are called ______. A. viroids B. phages C. prions D. oncogenic viruses E. spikes
A
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
B
A naked virus only has a/an ______. A. capsomere B. nucleocapsid C. envelope D. antigenic surface
B
A/an _____ is the protein shell around the nucleic acid core of a virus. A. capsomere B. capsid C. spike D. envelope E. monolayer
B
Compared to bacteria that have a typical size range between 1-10 m A. viruses range in size between 20-200 nm and are much larger than bacterial cells. B. viruses have a much greater size range; between 22 nm and 1000 nm. C. all viruses are 22 nm. D. viruses are larger and are blocked by sterilizing filters.
B
Diagnosis of viral infections sometimes involves analyzing the patient's blood for specific _____ that the immune system produces against the virus. A. glycoproteins B. antibodies C. complement proteins D. antigens
B
Freshly isolated animal tissue that is placed in a growth medium and allowed to produce a cell monolayer is referred to as a/n _____ cell culture. A. initial B. primary C. secondary D. continuous E. positive
B
In transduction, the viral genome A. initiates lysis of the host. B. includes DNA from the previous host. C. is replicated in the cytoplasm. D. is replicated in the nucleus.
B
Mammalian viruses capable of starting tumors are ______. A. chronic latent viruses B. oncoviruses C. syncytia D. inclusion bodies
B
Oncogenic viruses include all the following except ______. A. hepatitis B virus B. measles virus C. Papillomavirus D. HTLV-I and HTLV-II viruses E. Epstein-Barr virus
B
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.
B
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
Viruses exhibit all the following except ______. A. definite shape B. metabolism C. genes D. ability to infect host cells E. ultramicroscopic size
B
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
Which of the following is a true statement regarding lysogeny? A. Once the phage genome is integrated into the host cell, it remains there permanently. B. The host bacterial cell acquires new characteristics that are often detrimental to humans. C.It halts the viral life cycle because the phage genes are no longer replicated. D. The host bacterial cell is lysed once the phage genome is integrated.
B
Which of the following is not a viral order in the classification system? A. Caudovirales B. Vaccinia virus C. Nidovirales D. Mononegavirales
B
Which of the following represents a virus family name? A. Herpes simplex virus B. Herpesviridae C. Picornavirus D. Enterovirus E. Hepatitis B virus
B
A negative RNA virus must first A. synthesize a DNA copy of its genome. B. synthesize a negative RNA copy of its genome. C. synthesize a positive RNA copy of its genome. D. transcribe reverse transcriptase. E. transcribe RNA polymerase.
C
. The activation of a prophage is called ______. A. activation B. lysogeny C. transformation D. induction E. adsorption
D
A treatment for bacterial infections from the early 20th century has made a comeback; the use of bacterial viruses to eliminate bacterial infections. Which explanation most accurately describes the reason for the return of this treatment? A. A wide variety of bacteria cause a large percentage of human infections, producing much sickness and death. B. Viruses can infect bacteria, transferring pathogenic genes; the viral genes can then be suppressed, causing the bacteria to not replicate viruses. C. The attachment structures on the virus and the receptors on the host cells make for exquisite specificity of viruses for particular bacterial species. D. Antibiotic resistance in bacteria is on the increase, so using a different kind of therapy offers an alternative to traditional drugs.
D
Classification of viruses into families involves determining all the following characteristics except A. type of nucleic acid. B. type of capsid. C. presence of an envelope. D. biochemical reactions. E. number of strands in the nucleic acid
D
Creutzfeldt-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."
D
During lysogeny, an inactive prophage state occurs when the viral DNA is inserted into the host ______. A. cytoplasm B. nucleus C. nucleolus D. DNA E. cell membrane
D
Helical and icosahedral are terms used to describe the shape of a viral ______. A. spike B. capsomere C. envelope D. capsid E. core
D
In order to synthesize proteins, a virus with a genome comprised of single-stranded negative-sense RNA A. can directly translate its negative-sense RNA strand into proteins. B. must use reverse transcriptase to make a negative-sense DNA strand first. C. must use DNA polymerase to make a positive-sense DNA strand first. D. must use its negative-sense strand as a template to make a positive-sense RNA.
D
Reverse transcriptase synthesizes A. a positive RNA strand from a negative RNA strand. B. a negative RNA strand from a positive RNA strand. C. viral RNA from DNA. D. viral DNA from RNA
D
Some animals can become infected with multiple influenza virus strains usually associated with other animals. Which statement below describes the result of these infections? A. A new novel strain of flu may be produced, for which the human population has no immunity. B. Major genetic variations in the flu viruses can be reproduced. C. The viral genomes within the host cells can become recombined. D. All of the choices are correct.
D
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. makes the virus very susceptible to drug therapy
D
Viral classification has changed over the years and while they are given genus names, the use of species names has not been widely accepted. This is because A. viruses are not organisms. B. viruses change over time making species characteristics difficult to stabilize. C. viruses that could be classified into a single species may have many, but not all, properties in common. D. All of the above are arguments against using species designations for viruses.
D
Viral tissue specificities are called ______. A. ranges B. virions C. receptacles D. tropisms E. uncoating
D
Viruses acquire envelopes around their nucleocapsids during ______. A. replication B. assembly C. adsorption D. release E. penetration
D
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
Which of the following occurs during assembly? A. The nucleocapsid is formed. B. New viral nucleic acid is formed. C. Viral spikes insert in host cell membrane. D. The nucleocapsid is formed and viral spikes insert in host cell membrane. E. The viral envelope and the host cell membrane fuse
D
You are working in a laboratory that is studying a newly isolated virus. Your job is to culture the virus using in vitro methods. Upon observing your inoculated tissue culture specimen one day, you notice clumps of cells growing on top of the original monolayer of cells. Microscopic analysis of stained cells from the culture reveal an alteration in host cell membrane protein content and chromosomal structure. Based upon this information, you hypothesize that the virus you are studying is ______. A. a bacteriophage B. a prion C. a viroid D. an oncovirus E. a satellite virus
D
All of the following pertain to virus envelopes except A. gained as a virus leaves the host cell membrane. B. gained as a virus leaves the nuclear membrane. C. contain special virus proteins. D. help the virus particle attach to host cells. E. located between the capsid and nucleic acid
E
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
The core of every virus particle always contains ______. A. DNA B. capsomeres C. enzymes D. DNA and RNA E. either DNA or RNA
E
The primary purpose(s) of viral cultivation is/are to A. isolate and identify viruses in clinical specimens. B. prepare viruses for vaccines. C. do detailed research on viral structure, lifestyle, genetics, and effects on host cells. D. perform wide-scale harvesting of viruses. E. All of the choices are correct.
E
Two noncellular agents, smaller than viruses, are infectious proteins called _____ and infectious RNA strands called _____. A. prions; capsomeres B. virions; prions C. viroids; phages D. prions; phages E. prions; viroids
E
Uncoating of viral nucleic acid A. does not occur in bacteriophage multiplication. B. involves enzymatic destruction of the capsid. C. occurs during penetration in the multiplication cycle. D. occurs before replication. E. All of the choices are correct.
E
Viral growth in bird embryos can cause discrete, opaque spots in the embryonic membranes called ______. A. patches B. buds C. plaques D. cytopathic effects E. pocks
E
Viral nucleic acid types 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
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
t/f Animal viruses have the ability to attach to and enter almost any animal host cell.
False
t/f Bacteriophages do not undergo adsorption to specific host cell receptors prior to penetration.
False
t/f Each virus is classified into a genus based on its host, target tissue, and type of disease it causes
False
t/f The adeno-associated virus (AAV) and the delta agent are prions
False
t/f Viruses are considered ultramicroscopic because they range in size from 2 mm to 450 mm
False
t/f . Viruses are simple, noncellular, and lack mRNA.
True
t/f A fully formed virus that can cause an infection in a host cell is called a virion.
True
t/f Prophages can be activated into viral replication and enter the lytic cycle
True
t/f Spikes are glycoproteins that can be found projecting from the viral capsid
True
t/f Using species names for viruses is controversial since viruses are not considered living organisms, and they change over time so characteristics that may be used for speciation are unstable.
True
t/f Viral spikes are inserted into the host cell membrane before budding or exocytosis
True
t/f Viruses are the most common cause of acute infections that do not result in hospitalization.
True
t/f When a virus enters a host cell, the viral genes redirect the genetic and metabolic activities of the host cell
True
T-even phages ______. A. include the poxviruses B. infect Escherichia coli cells C. enter host cells by engulfment D. have helical capsids
b
What structures are used by bacteriophages to attach to host cell receptors? A. Viral sheaths B. Tail fibers C. Nucleic acids D. Capsid heads
b
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
Lysogeny refers to A. altering the host range of a virus. B. the latent state of herpes infections. C. virions exiting host cell. D. the viral genome inserting into bacterial host chromosome.
d
Which of the following is/are type(s) of cytopathic effects? A. Inclusions in the nucleus B. Multinucleated giant cells C. Inclusions in the cytoplasm D. Rounding of cells E. All of the choices are correct
e
t/f Viral nomenclature uses the same system as living organisms; a genus and specific epithet is designated for each virus
false
t/f Viruses are not filterable
false
t/f Viruses are unable to multiply outside of a host cell
true
t/f Viruses are used to produce vaccines for prevention of certain viral infections.
true
t/f Viruses mutate, and some viruses have not been discovered
true
New, nonenveloped virus release occurs by ______. A. lysis B. budding C. exocytosis D. both lysis and budding E. both budding and exocytosis
A
Persistent viruses that can reactivate periodically are ______. A. chronic latent viruses B. oncoviruses C. syncytia D. inclusion bodies E. cytopathic
A
Viral spikes A. are always present on enveloped viruses. B. attach the viral capsid and envelope. C. allow bacteria to evade host defenses. D. are derived from host proteins. E. are for recognition among the various types of viruses.
A
Viruses ______. A. cannot be seen in a light microscope B. are prokaryotic C. contain 70S ribosomes D. undergo binary fission
A
Viruses attach to their hosts via ______. A. host glycoproteins B. host phospholipids C. viral phospholipids D. viral flagella E. carbohydrate attachments of the viral capsid
A
Which of the following is not a typical capsid shape? A. Tetrahedral B. Complex C. Helical D. Icosahedron
A
Which of the following is not associated with every virus? A. Envelope B. Capsomeres C. Capsid D. Nucleic acid E. Genome
A
Why do some animal viruses have an external envelope, while bacteriophages never do? A. Some animal viruses bud out, taking part of the plasma membrane with them, whereas phages always lyse the host bacterial cell when they exit. B. When bacteriophages bud out, the plasma membrane is beneath the cell wall and therefore cannot be removed. C. When animal cells are lysed, part of the plasma membrane attaches to the virus; in bacterial cells, it is covered by the cell wall. D. When phages bud out of the host bacterial cell, they take with them part of the cell wall which forms the capsid, not an envelope
A
A treatment for bacterial infections from the early 20th century has made a comeback; the use of bacterial viruses to eliminate bacterial infections. Which explanation most accurately describes the mechanism of action behind this treatment? A. A wide variety of bacteria cause a large percentage of human infections, producing much sickness and death. B. Viruses can infect bacteria, transferring pathogenic genes. The viral genes can then be suppressed, causing the bacteria to not replicate viruses. C. The attachment structures on the virus and the receptors on the host cells make for exquisite specificity of viruses for particular bacterial species. D. Antibiotic resistance in humans is on the increase, so using a different kind of therapy is more beneficial.
C
Host range is limited by the 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.
C
How are viroids transmitted? A. Respiratory secretions B. Sex C. Plant seeds D. Blood products
C
Infectious protein particles are called ______. A. viroids B. phages C. prions D. oncogenic viruses E. spikes
C
One of the principal viral capsid shapes is a 20-sided figure with 12 evenly spaced corners referred to as a/an _____ capsid. A. spiked B. complex C. icosahedral D. helical E. buckeyball
C
Select the statement that most accurately describes the action of antimicrobial drugs today. A. Antiviral drug treatment is more effective than vaccination against a viral disease. B. Effective antiviral drugs have a long history of development and use. C. Antiviral drugs often result in toxic side effects due to their inhibition of host cell activity. D. The development of antiviral drug resistance has not been observed, as compared to the high rate of antibiotic resistance seen today
C
Sterilizing filters have a pore size of 0.22 m. Which of the following statements is true? A.Bacterial cells are typically between 1,000-10,000 nm and pass through the filter, whereas most viruses are between 20 and 200 nm and are therefore blocked. B.Bacterial cells are typically between 1-10 m and pass through the filter, whereas most viruses are between 20 and 200 nm and are therefore blocked. C.Bacterial cells are typically between 1-10 m and are blocked by the filter, whereas most viruses are between 20 and 200 nm and therefore pass through. D.Bacterial cells are typically between 1-10 nm and are blocked by the filter, whereas most viruses are between 20 and 200 m and therefore pass through
C
Successful anti-HIV drug therapies today work by blocking the action of viral reverse transcriptase. Select which step of virus multiplication that would be directly blocked by this mechanism. A. Adsorption B. Penetration C. Synthesis D. Assembly E. Release
C
Tamiflu is a common medication given for influenza treatment. It works by protecting and blocking sialic acid molecules on the surfaces of host cells and influenza virus envelopes as they leave the cell. Which statement reflects the mechanism of Tamiflu's action? A. Tamiflu blocks protein synthesis of the viral genome. B. Tamiflu interferes with the replication of +ssRNA from the -ssRNA genome of the flu virus. C. Tamiflu interferes with the release of the budding viruses from the infected host cells. D. Tamiflu interferes with the metabolic properties of the virus
C
The correct sequence of events in viral multiplication is A. penetration, uncoating, synthesis, adsorption, assembly, and release. B. uncoating, penetration, synthesis, assembly, absorption, and release. C. adsorption, penetration, uncoating, synthesis, assembly, and release. D. assembly, synthesis, uncoating, release, penetration, and adsorption. E. adsorption, release, synthesis, uncoating, assembly, and penetration
C
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
Viral capsids are made from subunits called ______. A. envelopes B. spikes C. capsomeres D. prophages E. peptones
C
Viruses that infect bacteria are specifically called ______. A. viroids B. prions C. bacteriophages D. satellite viruses
C
Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called ______. A. patches B. buds C. plaques D. cytopathic effects E. pocks
C
What type of phage enters an inactive prophage stage? A. Primary B. Secondary C. Temperate D. Temporary E. Transformed
C
Who developed a rabies vaccine after realizing the disease was caused by something smaller than a bacterium? A. Leeuwenhoek B. Koch C. Pasteur D. Cohn E. Ivanovski
C
Antiviral drugs are often difficult to develop, largely because A. viruses are obligate intracellular parasites so the drugs must enter the host cell and often cause toxic side effects in order to destroy the virus. B. viruses are more abundant in the body than bacterial cells. C. viruses are much smaller than bacterial cells. D. viruses are more pathogenic than bacterial cells.
a
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
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. intermediate; primary
a