Chapter 27 Flashcards
Virus morphology does not include which of the following characteristics?…
a.size
b.shape
c.presence or absence of an envelope
D.host range
Which of the following uses dsRNA as the genome?…
a.parvovirus
b.bunyavirus
C.rotavirus
d.poxvirus
Which of the following is(are) used in the classification of animal viruses?…
a.virion morphology
b.genome structure
c.genetic relatedness
D.all of the choices
(T/F) Viruses infecting algae have never been detected.
False
Which of the following represent(s) the way(s) in which enveloped viruses acquire their envelopes?….
a.Budding through the plasma membrane.
b.Budding through internal cellular membranes.
c.Viral enzymes are responsible for production of the envelope.
D.For some viruses, a is correct; for other viruses, b is correct.
Unlike most enveloped viruses, herpes viruses involve the host __________ membrane in the formation of their envelope…..
a.plasma
B.nuclear
c.mitochondrial
d.none of these
The most common type of molecule found on the surface of animal viruses for interacting with host cell receptors is a(n)…..
a.lipoprotein.
B.glycoprotein.
c.phosphoprotein.
d.teichoic acid.
Which of the following does not use RNA as the genome? ….
A.poxvirus
b.poliovirus
c.influenza virus
d.rabies virus
The largest viruses known are the….
a.herpesviruses.
b.hepadnaviruses.
c.adenoviruses.
D.mimiviruses.
A __________ infection is one in which the virus quits reproducing and remains dormant for a period before becoming active again. ….
a.persistent
B.latent
c.slow virus
d.none of these
In which of the following stages of the viral infectious cycle do enveloped viruses usually acquire their envelopes? …
a.penetration
b.component biosynthesis
c.assembly
D.release
(T/F) In viral infections involving double-stranded DNA viruses, all of the viral genes are usually expressed prior to the replication of viral nucleic acid.
False
(T/F) Parvoviruses are among the simplest known DNA viruses of animals.
True
A group of viruses thatcause severe diarrhea, resulting in over 600,000 deaths worldwide annually is the….
a.polioviruses.
B.rotaviruses.
c.poxviruses.
d.herpesviruses.
When a _________ enters a host cell, it loses the outermost protein layer and is then referred to by virologists as a double-layered particle (DLP).
rotavirus
(T/F) Tobacco mosaicvirus can be transmitted between individual plants by bitinginsects.
True
(T/F) One way in which small viruses package more information into a very small genome is to use overlapping genes so that the same base sequence is read in more than one reading frame.
True
(T/F) Almost all known plant viruses are RNA viruses.
True
(T/F) Although poliovirus capsids contain several distinct proteins, these are synthesized as a single polypeptide then cleaved by proteases to produce the individual proteins.
True
Influenza virus adheres to the epithelium of the respiratory system with the aid of _________ and _________ found in its envelope spikes.
neuraminidase; hemagglutinin
(T/F) Segmented genomes in negative-strand RNA viruses may have evolved from unsegmented ones; they may have been created by the reduction of redundant genetic regions.
True
The genomes of _____________________ cannot function as mRNA and therefore these viruses must bring at least one RNA-dependent RNA polymerase into the host cell during entry. ….
a.positive-strand RNA viruses
b.double-stranded DNA viruses
C.negative-strand RNA viruses
d.single-stranded DNA viruses
Retroviruses have a +ssRNA as their genome. In order to complete an infection, they must first make a __________ molecule, which they use to direct the synthesis of mRNA. …
a.dsRNA
B.dsDNA
c.DNA:RNA hybrid
d.-ssRNA
Which of the following must bring in a virion-associated RNA replicase when it infects host cells?….
a.+ssRNA viruses
B.-ssRNA viruses
c.+dsRNA viruses
d.all of the choices
The enzyme used by retroviruses to make a DNA copy of their RNA genome is called….
a.RNA polymerase.
b.DNA polymerase.
c.RNA replicase
.
D.reverse transcriptase.
Alpha, beta, gamma, and unclassified are the different families for what virus?
Herpes
What does Herpes target?
epithelial or nerve cells
Where does latent infections occur?
neuronal cells
infectious virus
infection recurs
How does herpes infect a cell?
fuses with the host cell membrane and their dsDNA enters the nucleus and replicates
Assembly and release of herpes?
nucleocapsid assembles and leaves
the virus envelope is made in the golgi
leaves
In epithelial cells, what protein enters the nucleus with the host cell factor?
VP16
In neurons, what protein enters with the host cell factor and doesn’t enter the cell?
VP16
How is rotavirus transmitted?
fecal matter
What strand cannot act as an mRNA for viral proteins?
negative strand
How many types of viruses are there for influenza?
three: ABC
Flu life cycle?
enters endosome
virus buds and leaves host and acquires envelope
Is polio nonenveloped?
yes
How is polio transmitted?
through digestion
What does retrovirus do to ssRNA?
converts into dsDNA
What does dsDNA serve as a template for?
mRNA
