Viral
enzymes are required for?
•
Interaction with receptors on host cell
•
transcribing the viral genome into mRNA
•
involved in copying virion RNA into DNA
•
Required for nucleic acid replication
What is
the viral enzyme neuraminidase required for?
•
Receptor-destroying enzyme
•
allows viruses to detach or elute from cells
In what
viruses is neuraminidase found?
•
Orthomyxoviruses
•
Paramyxoviruses
What does
the viral enzyme RNA-dependent DNA polymerase do?
•
It is used for reverse transcription
•
found in
–
retroviruses (RNA virus)
–
hepadnaviruses (DNA virus)
If a
virus has a positive (+) transcriptase, it cannot replicate in the host
cytoplasm.
•
F, If it has a (+) transcriptase it means that it is
providing its own transcriptase and therefore can divide in the cytoplasm.
All DNA
viruses are double stranded except?
•
Parvoviruses
•
Circoviruses
All RNA
viruses are single stranded except?
•
Reoviruses
•
birnaviruses
An
example of the RNA viruses that copy their genome into DNA is:
•
HIV
If an
virus contains a positive strand RNA, it acts directly as _____.
•
mRNA
What is a
prion?
•
Small, proteinaceous, infectious particle that is highly
resistant to heat, formalin, and chloroform.
What is
the suffix for family?
•
-viridae
What is
the suffix for subfamily?
•
-virinae
What is
the suffix for genera?
•
-virus
Viruses
are divided into families based on?
•
Size
•
symmetry
•
substructure
•
type of nucleic acid genome (RNA or DNA)
•
form of genome
–
Single stranded or Double stranded
–
segmented or nonsegmented
–
cyclic or linear
–
haploid or
diploid)
•
mode of replication
Viruses
are divided into genera and species based on?
•
Host species
•
pathogenesis
•
nucleic acid homology
•
antigenicity
Name 3
important characteristics of the Family Adenoviridae.
•
Possess filaments which project from vertex capsomeres -
help attach to cell
•
Form basophilic (blue) intranuclear inclusion bodies
•
Associated with latent infections
The genus
Parvovirus depends on _____ for replication and grows best in _____ and forms
____ in cell.
•
Cellular enzymes
•
rapidly dividing cells
•
acidophilic (red) intranuclear inclusion bodies when
stained with H & E.
Two
family of viruses which create intracytoplasmic inclulsion bodies are _____ and
____ and is a large virion.
•
Family Iridoviridae
•
Family Asfarviridae
The
viruses that belong to the Family herpesviridae mature by ________ and
therefore are ______.
•
Budding thruogh the nuclear membrane
•
Enveloped
Herpesvirus
form ______ in the cell nucleus.
•
Acidophilic (type A) intranuclear inclusion bodies
_____ is
a family of viruses that have an affinity for the liver.
•
Hepadnaviridae
What is pathoneumonic
of the viral family Hepadnariridae?
•
They are the only DNA virus with reverse
transcriptase.
What does
reverse transcriptase do for a DNA virus?
•
In an DNA virus, when the virus genome is first
translated, it is translated into RNA.
•
The reverse transcriptase is then used to translated
back into a DNA genome.
______
This family of viruses is the smallest known virus of vertebrates and plants.
•
Circoviridae
What type
of genome does the Family circoviridae have and where does replication occur?
•
Single stranded DNA genome
•
Replication occurs in the nucleus of cycling cells
What is
the genome of the family Togaviridae?
•
(+) sense RNA with envelope
•
Icosahedral nucleocapsid
•
ss RNA
What type
of genome does the family Reoviridae have?
•
(+) sense, ds RNA, segmented
Reoviridae
has a unique capsid. Describe it.
•
It possess a two-layered capsid
•
The capsomeres have holes
Describe
the inclusion bodies that Reoviridae produces.
•
Acidophilic perinuclear (c-shaped) inclusion bodies
What type
of genomes does the family Coronaviridae have?
•
(+) sense, ss RNA, enveloped
What is
unique about the envelope that is found around the capsid in the family Coronaviridae?
•
It possess unique club-shaped peplomeres projecting from
the envelope
Most
members of the Bunyaviridae are transmitted by _____.
•
ARTHROPODS
What type
of genome does the family Bunyaviridae have?
•
(+) sense, ss RNA, enveloped
•
carries its own transcriptase
The
influenza virus falls into this family: ____
•
Orthomyxoviridae
The Orthomyxoviridae
have what type of genome?
•
(_) sense RNA; segmented (7-8 segments); enveloped
•
carries its own transcriptase
The Orthomyxoviridae
have glycoprotein peplomeres consisting of ____ and _____.
•
Hemagglutinin and
•
neuraminidase
Where
does replication of Orthyomyxoviridae take place?
•
In the nucleus and cytoplasm of the host cell
Why is
dual infection in the Orthyomyxoviridae important?
•
It provides the virus with the possibility of genetic reassortment
creating new flu viruses.
This family
have pleomorphic virons:_____
•
Paramyxoviridae
True or
False. The Paramyxoviridae form both intracytoplasmic
and intranuclear inclusion bodies.
·
T
True or
False. All Paramyxoviridae possess both hemaglutinin
and/or neuraminidase.
•
F. Only some of
them possess these.
True or
False. Canine distemper virus is a memmber
of the Retroviridae family.
•
F. It is a member
of the Paramyxoviridae family
The type
of inclusion bodies that the rabies virus produces are called _____
•
Negri bodies (red intracytoplasmic inclusion bodies)
The virion
in this family resembles a bullet:_____
•
Rhabdorviridae
What type
of genome does the family Retroviridae have?
•
(+) sense , ss, RNA; enveloped
•
carries its own transcriptase
The
family Retroviridae is unique in that it prosses a ____ and,
this family possess all RNA ____ viruses and
these viruses cause _____________.
•
Reverse transcriptase
•
oncogenic
•
permanent infections with periods of latency
True or
False. All oncogenic viruses are
classified in the family Retroviridae BUT
, not all
Retroviridae virions are oncogenic.
–
T
____ is
and important human virion and ____ is an important feline virion which both
fall into the family Retroviridae.
•
HIV
•
FIV
The Birnaviridae
family has a ______ genome.
•
Ds RNA
•
possess own transcriptase
What does
a segmented genome allow?
•
Genetic reassortment
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