viruses Flashcards
what does virus mean in latin
poison
true or false, viruses contain two types of nucleic acids in their genome
false, only DNA or RNA not both
what are viruses that infect other viruses called
virophage
…….. only infects humans and …….. only infects warm-blooded animals
poliovirus and rabiesvirus
what is the key step in viral life cycle
viral assembly. viruses do replicate by assembly
what does viral assembly involve
protein associations and interactions between the viral genome and capsid proteins
what are new virions called
daughter viruses or progeny virions
what is the protein shell, or coat, that encloses the nucleic acid genome
capsid
what are capsomeres
Morphologic units on the surface of icosahedral virus particles
what is the lipid-containing membrane that surrounds some virus particles acquired during viral maturation
envelope
what is the nucleocapsid
protein–nucleic acid complex representing the packaged form of the viral genome
what is a protomer
basic structural unit (basic protein building blocks of the coat). they self-assemble to form a capsomere and capsomeres self-assemble to form a capsid
what is the complete virus particle called
virion
what are viriods
Consist only of a short strand of circular RNA capable of self replication and don’t have a protein coat
Virusoids
non–self-replicating ssRNAs (require that the cell also be infected with a specific “helper” virus)
give one example of satellite RNA that infects humans as a virusoid
hepatitis delta virus (HDV)
what is a misfolded rogue form of a normal protein (PrPc) found in the cell
prions(PrPsc). Prions do not contain DNA or RNA
what are prions known to have caused
transmissible spongiform encephalopathy (TSE) in animals and humans
which of these are highly resistant to inactivation by heat, formaldehyde, and ultraviolet light
a) virusoids
b) prions
c) viroids
d) virions
prions.
what is the seven basis of classification of viruses
- Virion morphology,
- Virus genome properties,
- Genome organization and replication,
- Virus protein properties,
- Antigenic properties.
- Physicochemical properties
- Biologic properties
MGOPAPB
Virus family names have the suffix……….
viridae
Genus names carry the suffix……….
virus
what is the genus suffix of subfamily and order
virinae and virales
give an example of
a) dsDNA virus
b) ssDNA virus
a) herpesviridae
b) circoviridae
what family is Hepatitis B virus
hepadnaviridae
DNA genomes reside in the nucleus except for what family of viruses
poxviruses
what do late genes and early genes encode
early genes- DNA-binding proteins and enzymes
late genes- structural and other proteins
give dsRNA viruses
Reoviridae
picornaviridae
name negative strand ssRNAs
Orthomyxoviridae
Paramyxoviridae
Filoviridae
Arenaviridae
which are not to mutations. RNA or DNA viruses
RNA viruses
RNA viruses, except ………. must carry polymerases
(+) RNA genome
which viruses are all enveloped
(−) RNA viruses
which of the following is false
a) (+) RNA similar to mRNA
b) (−) RNA complementary to mRNA
c) (+) RNA can be immediately translated by host cell
d) (−) RNA can be immediately translated by host cell
d) becaucse (−) RNA has to be converted to (+) RNA in order to be translated by host cell
give examples of enveloped viruses
HIV, HSV, influenza
give examples of non-enveloped viruses
Norovirus, Parvovirus, HAV, HEV
what structure in influenza agglutinates red blood cells
hemagglutinin
what are the four groups of enzymes have been detected in the viruses
a. Neuraminidase
b. RNA polymerase
c. Reverse transcriptase
d. Enzymes of cellular origin
what are the two groups of viral proteins
a. Structural proteins
b. Non-structural proteins (functional proteins e.g haemagglutinins)
where do lipids present in viruses originate from
the host’s cell membrane
give an example of a virus with RNA that is single linear
molecule
picornaviruses
give an example of a virus with RNA which has genome consists of several segments
orhomyxoviruses
how are single stranded RNA classified
negative-sense
positive-sense,
ambisense RNA viruses
examples of negative strand RNA viruses
influenza virus, measles viruses, and rabies virus
what is the function of the capsid
encloses the nucleic acid genome, that protect the genome and confer shapes to viruses
what are the two main structural types of the capsid
- cylindrical (helical symmetry)
- spherical (icosahedral or cubic symmetry)
what are the advantages of naked capsids
- resistant to drying, acid, and detergents, including the acid and bile of the enteric tract
- spreads easily
- retain effectivity
what is a peplomer
glycoprotein spike on a viral capsid or viral envelope
what is the function of the matrix protein
serves as a bridge between nucleocapsid and inner membrane of the envelope
what viruses are sensitive to treatment with ether and other organic solvents
Lipid-containing viruses
instead of lipids in viral membranes, what do viral envelopes contain
glycoprotein
what are glycoproteins in viruses important as
viral antigens
what are the types of symmetry of viral particles and give examples for each
(1) cubic symmetry (eg, adenoviruses),
(2) helical symmetry (eg, orthomyxoviruses),
(3) complex structures (eg, poxviruses)
which viruses have cubic symmetry
spherically (icosahedral) shaped virus
what viruses have icosahedral structure
poliovirus, rhinovirus, and adenovirus
how many individual protein molecules is a capsomere generally composed of
five or six, each one referred to as a structural subunit, or protomer. 5 protomers then form a pentomer
how are the protein subunits bound to the nucleic acid in cylindrical arch structure
bound in a periodic way, bound in a periodic way
give an example of a virus with cylindrical arch structure
Rabies virus
which extra structures may complex viruses have
protein tails or a complex outer wall
what is an example of a complex virus
poxviruses (do not contain clearly identifiable capsids, but have several coats around the nucleic acid)
what are the three basic types of cell cultures
Primary cultures
Diploid cell lines
Continuous cell lines
how to detect Virus-Infected Cells
1) Development of cytopathic effects (morphological changes)
2) Appearance of a virus-encoded protein
3) Detection of virus-specific nucleic acid
4) Adsorption of erythrocytes to infected cells, called hemadsorption
5) Viral growth in an embryonated chick egg may result in death of the embryo
where are inclusion bodies located in
a) herpesvirus
b) poxvirus and rabies virus
c) measles virus
a) nucleus
b) cytoplasm
c) both nucleus and cytoplasm
