Chapter 7 objectives Flashcards
Reverse transcriptase synthesizes:
viral DNA from RNA.
a positive RNA strand from a negative RNA strand.
viral RNA from DNA.
a negative RNA strand from a positive RNA strand.
viral DNA from RNA.
Viruses acquire envelopes around their nucleocapsids during:
replication.
release.
penetration.
adsorption.
release.
Infectious naked strands of RNA that affect plants are called
spikes.
viroids.
phages.
prions.
viroids.
Viral growth in bird embryos can cause discrete, opaque spots in the embryonic membranes
patches.
pocks.
buds.
plaques.
pocks.
Tamiflu is a common medication given for influenza treatment, its action being to protect and block 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?
Tamiflu interferes with the replication of +ssRNA from the -ssRNA genome of the flu virus.
Tamiflu interferes with the release of the budding viruses from the infected host cells.
Tamiflu blocks protein synthesis of the viral genome.
Tamiflu interferes with the metabolic properties of the virus.
Tamiflu interferes with the release of the budding viruses from the infected host cells.
Which of the following represents a virus family name?
Herpes simplex virus
Picornavirus
Herpesviridae
Enterovirus
Hepatitis B virus
Herpesviridae
Infectious protein particles are called
viroids.
spikes.
phages.
prions.
prions.
Freshly isolated animal tissue that is placed in a growth medium and allowed to produce a cell monolayer is referred to as a/n _____.
secondary
initial
primary
positive
continuous
primary
Select the statement that most accurately describes the action of antimicrobial drugs today.
Antiviral drugs often result in toxic side effects due to their inhibition of host cell activity.
The development of antiviral drug resistance has not been observed, as compared to the high rate of antibiotic resistance seen today.
Antiviral drug treatment is more effective than vaccination against a viral disease.
Effective antiviral drugs have a long history of development and use.
Antiviral drugs often result in toxic side effects due to their inhibition of host cell activity.
Which of the following is correct about prophages?
present when the virus is in lysogeny
formed when viral DNA enters the bacterial chromosome
cause lysis of host cells
occur when temperate phages enter host cells
Present when the virus is in lysogeny
Formed when viral DNA enters the bacterial chromosome
Occur when temperate phases enter host cells
During lysogeny, an inactive prophage state occurs when the viral DNA is inserted into the host
cytoplasm.
nucleus.
DNA.
cell membrane.
DNA
Viral tissue specificities are called
ranges.
tropisms.
virions.
receptacles.
tropisms.
Creutzfeldt-Jacob disease is
also called “mad cow disease.”
caused by a chronic latent virus.
a spongiform encephalopathy of humans.
initiated by an oncogenic virus.
a spongiform encephalopathy of humans.
The event that occurs in bacteriophage multiplication that does not occur in animal virus replication is:
host cell synthesis of viral enzymes and capsid proteins.
injection of only the viral nucleic acid into the host cell.
assembly of nucleocapsids.
adsorption to the host cells.
injection of only the viral nucleic acid into the host cell.
New, nonenveloped virus release occurs by
exocytosis.
lysis.
both lysis and budding.
budding.
lysis.
Viral capsids are made from subunits called:
spikes.
peptones.
capsomeres.
envelopes.
capsomeres.
Some animals can become infected with multiple influenza virus strains usually associated with other animals. Which statement below describes the result of these infections?
All are possible outcomes.
The viral genomes within the host cells can become recombined.
Major genetic variations in the flu viruses can be reproduced.
A new novel strain of flu may be produced, for which the human population has no immunity.
All are possible outcomes.
One of the principal viral capsid shapes is a 20-sided figure with 12 evenly spaced corners referred to as a/n _____ capsid.
icosahedral
complex
helical
spiked
icosahedral
A common method for cultivating viruses in the lab is to use in vitro systems called _____ cultures.
cell
egg
plaque
embryo
bacteriophage
cell
Viral nucleic acid types include:
Group of answer choices
single-stranded RNA
single-stranded DNA
All of the choices are correct.
double-stranded RNA
double-stranded DNA
All of the choices are correct.
When a bacterium acquires a trait from its temperate phage, it is called
Group of answer choices
transformation.
viral persistence.
lysogenic conversion.
translation.
transcription.
lysogenic conversion.
Viral spikes
Group of answer choices
are derived from host proteins.
are always present on enveloped viruses.
attach the viral capsid and envelope.
allow bacteria to evade host defenses.
are for recognition among the various types of viruses.
are always present on enveloped viruses.
Which of the following will not support viral cultivation?
Group of answer choices
continuous cell cultures
embryonated bird eggs
live lab animals
All of the choices will support viral cultivation.
primary cell cultures
All of the choices will support viral cultivation.
The envelope of enveloped viruses
Group of answer choices
is obtained by viral budding or exocytosis.
is identical to the host plasma membrane.
always includes spikes.
makes the virus very susceptible to drug therapy.
is only composed of host endomembrane.
is obtained by viral budding or exocytosis.
Satellite viruses are
Group of answer choices
also called viroids.
dependent on other viruses for replication.
the cause of spongiform encephalopathies.
significant pathogens of plants.
dependent on other viruses for replication.
Viruses
Group of answer choices
undergo binary fission.
cannot be seen in a light microscope.
are prokaryotic.
contain 70S ribosomes.
cannot be seen in a light microscope.
A naked virus only has a/n
Group of answer choices
envelope.
capsomere.
capsid.
antigenic surface.
nucleocapsid.
nucleocapsid.
What type of phage enters an inactive prophage stage?
Group of answer choices
temporary
temperate
primary
transformed
secondary
temperate
Viruses exhibit all the following except
Group of answer choices
genes.
metabolism.
ultramicroscopic size.
definite shape.
ability to infect host cells.
metabolism.
Oncogenic viruses include all the following except
Group of answer choices
measles virus.
HTLV-I and HTLV-II viruses.
Papillomavirus.
Epstein-Barr virus.
hepatitis B virus.
measles virus.
Which of the following is a type of cytopathic effect?
Group of answer choices
multinucleated giant cells
inclusions in the nucleus
inclusions in the cytoplasm
All of the choices are correct.
rounding of cells
All of the choices are correct.
How are viroids transmitted?
Group of answer choices
plant seeds
blood products
respiratory secretions
sex
plant seeds
A/n _____ is the protein shell around the nucleic acid core of a virus.
Group of answer choices
spike
capsid
monolayer
capsomere
envelope
capsid
Viruses attach to their hosts via
Group of answer choices
host glycoproteins.
viral phospholipids.
viral flagella.
carbohydrate attachments of the viral capsid.
host phospholipids.
host glycoproteins.
Which of the following is not a typical capsid shape?
Group of answer choices
viroid.
tetrahedral
helical
complex
icosahedron
tetrahedral
Uncoating of viral nucleic acid
Group of answer choices
does not occur in bacteriophage multiplication.
involves enzymatic destruction of the capsid.
occurs before replication.
All of the choices are correct.
occurs during penetration in the multiplication cycle.
All of the choices are correct.
Mammalian viruses capable of starting tumors are
Group of answer choices
cytopathic.
oncoviruses.
syncytia.
inclusion bodies.
chronic latent viruses.
oncoviruses.
The correct sequence of events in viral multiplication is:
Group of answer choices
adsorption, penetration, uncoating, synthesis, assembly, release
penetration, uncoating, synthesis, adsorption, assembly, release
uncoating, penetration, synthesis, assembly, absorption, release
adsorption, release, synthesis, uncoating, assembly, penetration
assembly, synthesis, uncoating, release, penetration, adsorption
adsorption, penetration, uncoating, synthesis, assembly, release
Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called
delta agents.
latent.
viroids.
oncogenic.
prions.
latent.
A common method for cultivating viruses in the lab is to use in vitro systems called _____ cultures.
Group of answer choices
embryo
cell
egg
plaque
bacteriophage
cell
Persistent viruses that can reactivate periodically are
Group of answer choices
cytopathic.
inclusion bodies.
oncoviruses.
chronic latent viruses.
syncytia.
chronic latent viruses.
The activation of a prophage is called
Group of answer choices
transformation.
induction.
activation.
lysogeny.
adsorption.
induction.
Which of the following is not a viral order in the classification system?
Group of answer choices
Vaccinia virus
Nidovirales
Caudovirales
Mononegavirales
Vaccinia virus
Two noncellular agents, smaller than viruses, are infectious proteins called _____ and infectious RNA strands called _____.
virions; prions
viroids; phages
prions; phages
prions; capsomeres
prions; viroids
prions; viroids
Which of the following is not a characteristic of a transformed cell?
Group of answer choices
viral nucleic acid integrated into host DNA
changes in cell surface molecules
alterations in chromosomes
capacity to divide indefinitely
decreased growth rate
decreased growth rate
Host cells of viruses include
Group of answer choices
bacteria.
All of the choices are correct.
humans and other animals.
plants and fungi.
protozoa and algae.
All of the choices are correct.
Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called
Group of answer choices
patches.
pocks.
cytopathic effects.
plaques.
buds.
plaques.
In general, most DNA viruses multiply in the host cell’s _____, while most RNA viruses multiply in the host cell’s _____.
Group of answer choices
nucleus; endoplasmic reticulum
cytoplasm; cell membrane
cell membrane; cytoplasm
cytoplasm; nucleus
nucleus; cytoplasm
nucleus; cytoplasm
The core of every virus particle always contains
Group of answer choices
DNA and RNA.
capsomeres.
DNA.
enzymes.
either DNA or RNA.
DNA and RNA.
Classification of viruses into families involves determining all the following characteristics except
Group of answer choices
biochemical reactions.
presence of an envelope.
number of strands in the nucleic acid.
type of nucleic acid.
type of capsid.
biochemical reactions.
Diagnosis of viral infections sometimes involves analyzing the patient’s blood for specific _____ that the immune system produces against the virus.
Group of answer choices
antibodies
complement proteins
glycoproteins
antigens
antibodies
Which of the following is not associated with every virus?
capsid
envelope
nucleic acid
capsomeres
envelope
Viruses with _____-sense RNA contain the correct message for translation, while viruses with _____-sense RNA must first be converted into a correct message.
Group of answer choices
negative; positive
secondary; primary
intermediate; primary
positive; negative
positive; negative
All of the following pertain to virus envelopes except
Group of answer choices
gained as a virus leaves the host cell membrane.
located between the capsid and nucleic acid.
help the virus particle attach to host cells.
gained as a virus leaves the nuclear membrane.
located between the capsid and nucleic acid.
Cells grown in culture form a/n
Group of answer choices
plaque.
monolayer.
aggregate.
bilayer.
monolayer.
Which of the following occurs during assembly?
Group of answer choices
nucleocapsid is formed
nucleocapsid is formed and viral spikes insert in host cell membrane
viral spikes insert in host cell membrane
the viral envelope and the host cell membrane fuse
new viral nucleic acid is formed
nucleocapsid is formed and viral spikes insert in host cell membrane
Lysogeny refers to
Group of answer choices
viral genome inserting into bacterial host chromosome.
latent state of herpes infections.
altering the host range of a virus.
virion exiting host cell.
viral genome inserting into bacterial host chromosome.
Viruses that infect bacteria are specifically called
Group of answer choices
viroids.
prions.
bacteriophages.
satellite viruses.
bacteriophages.
Host range is limited by
Group of answer choices
age of the host cell.
size of the host cell.
type of nucleic acid in the virus.
type of host cell receptors on cell membrane.
type of host cell receptors on cell membrane.
Helical and icosahedral are terms used to describe the shape of a viral
Group of answer choices
core.
capsomere.
spike.
capsid.
envelope.
capsid.
Infant wheezing with trouble breathing:
Norovirus
Rubella
Mumps
Polio
Hantavirus
Rotavirus
Respiratory Syncytial Virus
Respiratory Syncytial Virus (RSV)
Nausea, vomiting, fever sometimes associated with cruise ships, nursing homes
Norovirus
Rubella
Mumps
Polio
Hantavirus
Rotavirus
Respiratory Syncytial Virus
Norovirus
Vaccine preventable, may cause paralysis, attempts to eradicate underway
Norovirus
Rubella
Mumps
Polio
Hantavirus
Rotavirus
Respiratory Syncytial Virus
Polio
In 1964, 20,000 babies were born with defects due to this virus
Norovirus
Rubella
Mumps
Polio
Hantavirus
Rotavirus
Respiratory Syncytial Virus
Rubella
May cause serious viral gastroenteritis in infants, leading cause of viral gastroenteritis worldwide, newer vaccine available
Norovirus
Rubella
Mumps
Polio
Hantavirus
Rotavirus
Respiratory Syncytial Virus
Rotavirus
Rodent control may prevent this; remember to never sweep a shed with rodent feces!
Norovirus
Rubella
Mumps
Polio
Hantavirus
Rotavirus
Respiratory Syncytial Virus
Hantavirus
Inflammation of salivary glands
Norovirus
Rubella
Mumps
Polio
Hantavirus
Rotavirus
Respiratory Syncytial Virus
Mumps
