Virology M/C Questions from document Flashcards
The term “viral virulence” relates to:
a. The ability of the virus to cause disease in its natural host species.
b. The ability of the virus to cause cytopathic effects (CPE) in cell culture.
c. The ability of the virus to cause disease in humans.
d. The ability of the virus to spread systemically and infect a variety of tissues.
e. The ability of the virus of cause disease in a specified host.
e. The ability of the virus of cause disease in a specified host.
Choose the best answer to finish the sentence: Swabs for virological investigation should be collected…
a. Into a commercially available aerobic bacteriological swab - the medium provided with these swabs is suitable for both viral and bacteriological samples.
b. Into a commercially available anaerobic bacteriological swab - the medium provided with these swabs is suitable for both viral and bacteriological samples.
c. Dry into a sterile container (e.g. red top blood tube), so that any viruses present will not be diluted by the medium.
d. Into a viral transport medium, which contains proteins to stabilize the virus and antibiotics to prevent bacterial growth.
e. Into a sterile EDTA blood tube if the swab contains bloody discharge, so that it won’t coagulate during transport to the laboratory.
d. Into a viral transport medium, which contains proteins to stabilize the virus and antibiotics to prevent bacterial growth.
The samples for virological investigation should be transported to the laboratory:
a. As soon as possible, preferably within 24 hours of collection. The samples should be put in a freezer immediately after collection and then thawed when ready for transport. The samples should be transported cold with ice packs.
b. As soon as possible, preferably within 24 hours of collection. The samples should be kept cold, but not frozen after collection and during transport.
c. Within a week of collection, providing they are kept in a fridge.
d. As soon as possible, preferably within 24 hours of collection. If the samples are transported to the laboratory soon after collection there is no need to maintain the cold chain during transport.
e. Any time after collection as long as the samples are maintained in the fridge. If the samples were collected using sterile technique all viruses will survive in the fridge for extended periods of time.
b. As soon as possible, preferably within 24 hours of collection. The samples should be kept cold, but not frozen after collection and during transport.
Which of the following statements about virus size and complexity is most true?
a. The smallest viruses are smaller than viroids.
b. The largest viruses are about as complex as Escherichia coli.
c. The largest viruses can replicate independently of living cells.
d. The smallest viruses consist only of protein
e. The smallest viruses are larger than prions.
e. The smallest viruses are larger than prions.
Which of the following is least useful as a basis for classifying viruses
into families?
a. DNA or RNA genome.
b. Double-stranded or single-stranded genome.
c. Intranuclear or intracytoplasmic inclusion bodies.
d. Helical, icosahedral, or complex structural symmetry.
e. Enveloped or non-enveloped virions.
c. Intranuclear or intracytoplasmic inclusion bodies.
Which of the following stages in the virus replication cycle is the drug Tamiflu thought to target?
a. Adsorption.
b. Attachment.
c. Uncoating.
d. Synthesis.
e. Release.
e. Release.
Soluble CD4 has been used experimentally as an anti-HIV drug and may yet prove useful in veterinary medicine. Which of the following stages in the virus replication cycle is it thought to target?
a. Adsorption.
b. Attachment.
c. Uncoating.
d. Synthesis.
e. Release.
b. Attachment.
Which of the following is the most commonly and widely used method for the cultivation of mammalian viruses?
a. Organ cultures.
b. Experimental animals.
c. Primary cell cultures.
d. Secondary cell cultures.
e. Continuous cell lines.
e. Continuous cell lines.
- A cytopathic effect (CPE) is sometimes observed when cultivating viruses in vitro. Which of the following statements about CPE is most correct?
a. Some kinds of virus cause a characteristic CPE. For example, herpesviruses tend to cause formation of syncytia.
b. Dead cells, killed by the virus, tend to look large, angular, and paler than surrounding healthy, uninfected cells.
c. It may take weeks for a CPE to develop. Multiple cell passages may have to be done before CPE can be observed.
d. Some kinds of virus grow very well in cell culture but cause no CPE whatsoever.
e. If CPE develops very rapidly, it may be difficult to distinguish it from cytotoxicity
due to a toxic substance in the clinical specimen (i.e., the inoculum).
a. Some kinds of virus cause a characteristic CPE. For example, herpesviruses tend to cause formation of syncytia.
b. Dead cells, killed by the virus, tend to look large, angular, and paler than surrounding healthy, uninfected cells.
c. It may take weeks for a CPE to develop. Multiple cell passages may have to be done before CPE can be observed.
d. Some kinds of virus grow very well in cell culture but cause no CPE whatsoever.
Which of the following are viral non-structural proteins? Choose all correct answers (there may be more than one).
a. Integrase.
b. Reverse transcriptase.
c. Hyaluronidase.
d. Hexokinase.
e. Peplomerase.
a. Integrase.
b. Reverse transcriptase.
Which of the following statements about viral structure are true? Choose all correct answers (there may be more than one).
a. Structural symmetry facilitates virion self-assembly.
b. Cubic symmetry is a synonym for icosahedral symmetry.
c. Individual virus families contain viruses of helical or icosahedral symmetry, but not both.
d. Virions with complex symmetry have both helical and icosahedral symmetry.
e. Helical symmetry is a feature of the viral nucleocapsid, not of the envelope.
a. Structural symmetry facilitates virion self-assembly.
b. Cubic symmetry is a synonym for icosahedral symmetry.
c. Individual virus families contain viruses of helical or icosahedral symmetry, but not both.
e. Helical symmetry is a feature of the viral nucleocapsid, not of the envelope.
Laboratory results of virus isolation are usually available:
a. Within 24-48 hours. This is how long it takes for viral colonies to become visible on agar plates.
b. Within 2-3 days for positive samples, but it may take up to 1 week for negative samples, as these are typically passaged in the appropriate cells 2-3 times before being reported as negative.
c. Within 1-3 weeks for positive samples, but it may take up to one month or longer for negative samples, as these are typically passaged in the appropriate cells 2-3 times before being reported as negative.
d. Within 24-48 hours, as viruses multiply very fast and typically millions of viruses are produced from one infected cell within hours.
e. Within 1 week for negative samples, but it may take longer for positive samples, as the viruses cultured would have to be further identified.
c. Within 1-3 weeks for positive samples, but it may take up to one month or longer for negative samples, as these are typically passaged in the appropriate cells 2-3 times before being reported as negative.
Which of the following statements about viral genomes is least true?
a. Most DNA virus families have double-stranded genomes.
b. Some RNA viruses have segmented genomes, but there are no DNA viruses with segmented genomes.
c. There are no known RNA viruses with circular genomes.
d. DNA virus genomes vary in size much more than do RNA virus genomes.
e. There are no known RNA viruses with double-stranded genomes.
c. There are no known RNA viruses with circular genomes.
T/F Antiviral drugs inhibit specific steps in viral replication.
True
T/F Resistance to antiviral drugs is very rare, as viruses cannot change as rapidly as bacteria.
False
