Inro To Virology Flashcards
A virus is an infectious agent that is minimally constructed of two components:
1) a ____
2) a ____
genome
capsid
a genome of a virus consists of either ribonucleic acid (RNA) or deoxyribonucleic acid (DNA), or both
T/F
F
Not both
a capsid is a ____-containing structure designed to _____
protein
protect the genome.
A complete virus particle combining these structural elements is called a ______.
virion
Terminology
-Virion: The ______
-Capsid: The —— that surrounds ___
-Nucleocapsid: The ____ plus the ____.
-Capsomeres: The _______
complete virus particle.
protein coat; nucleic acid.
nucleic acid; capsid
structural protein units that made up the capsid.
Terminology
Surface Proteins: These are _____ found on the ____ of viruses that facilitate ______ of the virion into host cells.
glycoproteins
lipid envelope
attachment and entry
Viral Envelope: This is the _____ of some types of viruses. Usually derived from portions of the _____ and includes some ______
outermost layer
host cell membranes
viral glycoproteins.
Characteristics of VIRUSES
Viruses range in size between __-__ nanometers ( nm ).
20-300
Viruses are (smaller or larger ?) than bacteria
Smaller
Viruses possess cellular organelles, such as mitochondria and ribosomes.
T/F
F
They lack it
Viruses are obligate cellular parasites , meaning that They _________
replicate only inside living cells.
Viruses replicate through replication of their ______ and synthesis of the ____
nucleic acid
viral protein.
Viruses do not multiply in chemically defined media.
T/F
T
Viruses undergo binary fission
T/F
F
They do not
CLASSIFICATIONS
Viruses are classified based on
-_____
-______
-______
type and structure of the viral nucleic acid (Genome)
-type of symmetry of the virus capsid (Capsid Symmetry)
-presence or absence of a lipid envelope. (Envelope)
Based on the genome
-____viruses or ___ viruses
-_____ or ____
-_____stranded or ____ stranded
DNA; RNA
Linear or Circular
Single; double
some viruses are also recognized as segmented.
T/F
T
DNA GENOME
*Linear genome: ______,______, and ____
*Circular genome: _____ and ____ and ______
adenoviruses, herpesviruses, and poxviruses
polyomaviruses and hepadnaviruses and papilloma virus
RNA GENOME
(1)Positive-sense (+) RNA
-Directly translated into protein
T/F
T
Positive-sense (+) RNA genome has (Same or different?) sequence as _____
Same
messenger RNA (mRNA)
Exception to the Positive-sense (+) RNA viruses is the _____ in which the (+) RNA genome is ____ but is converted into ___, which then acts as ______
retroviruses
not translated
DNA
a template for production of mRNA.
Negative-sense (-) RNA
The Sequence is (identical or complementary?) to mRNA
complementary
Negative-sense (-) RNA
Must be copied into mRNAs for protein synthesis
T/F
T
Double-stranded (+/–) RNA:
copying of (- or +?) strand generates mRNA for protein synthesis
(-)
Segmented GENOME
-Found in the __viruses, a dsRNA genome, and in three families of (-) ssRNA viruses (____viruses, __viruses, and ___viruses)
-Consists of several pieces, or segments, each of which encodes at least one polypeptide
reo
orthomyxo; arena; bunya
Segmented genome viruses
Can’t undergo reassortment among genomic segments
T/F
F
It may
Based ON CAPSID SYMMETRY
(1)____
(2)______
(3)_____
Based ON THE Envelope
____
_____
Cubic
Helical
Complex
Naked
Enveloped
Based ON CAPSID SYMMETRY
(1)Cubic
The virus particle is _____ in shape (almost ____ particle ) and the nucleic acid contained inside the capsid.
(2)Helical
The virus particle is _____ or ______ , and the nucleic acid is _____
(3)Complex
The virus particle does is ???
icosahedral
spherical
elongated or pleomorphic
spiral
not confirm either cubic or helical symmetry.
DNA VIRUSES
The _____ viruses( the acronym)
HHAPPPPy
DNA viruses!!!
Single stranded unenveloped = ____
Double stranded enveloped=________
Double stranded unenveloped = _________
parvo
Hepadna, herpes, pox
Adeno,papilloma, polyoma
Parvo- linear or circular
Hepadna- linear or circular
Herpes-linear or circular
Pox - linear or circular
Adeno- linear or circular
Papilloma -linear or circular
Polyoma- linear or circular
Linear
Circular
Linear
Linear
Linear
Circular
Circular
Largest DNA virus = ____
Smallest DNA virus = ____
pox
parvo
Only DNA virus that doesn’t replicate in the nucleus =___
POX
Based ON THE Envelope
Naked
Enveloped
Which is sensitive/resistant to heat,acid,detergent,dying?
Effect of drying?
Naked is resistant; enveloped is sensitive
Naked-retain infectivity ; enveloped-lose infectivity
How are enveloped and baked viruses Released from host cell??
And does the host cell survive
Naked- By cell lysis (host cell killed)
By budding(host cell survives)
Survival of naked and enveloped viruses within GIT
And state the exceptions
Naked- yes
Enveloped-no . Except Corona and Hepadna
Mode of spread of naked viruses
Mode of spread of enveloped viruses
Naked-Formites,dust,fecal-oral
Enveloped-Secretions, organ or blood transplants, large droplets
Components of naked viruses include
Phospholipids, proteins, glycoproteins
T/F
F
Only proteins
The rest are for enveloped viruses
Immune response to naked viruses??
Antibody response
Immune response to enveloped viruses??
Antibody and cell mediated responses that contributes to pathogenesis
all RNA viruses replicate in the cytoplasm except _____ and ____ virus
retrovirus and influenza
Reovirus
Naked or enveloped
Single or double stranded
Linear or circular
Capsid symmetry?
Examples
Naked
Double
Linear
Icosahedral
Coltivirus
Rotavirus
Picornaviruses
Naked or enveloped
Single or double stranded
Linear or circular
Capsid symmetry?
Examples
Naked
Single
Linear
Icosahedral
PERCH
polio,echo,rhino, coxsackie HAV
Hepevirus
Naked or enveloped
Single or double stranded
Linear or circular
Capsid symmetry?
Examples
Enveloped
Double
Linear
Icosahedral
HSV
Calicivirus
Naked or enveloped
Single or double stranded
Linear or circular
Capsid symmetry?
Examples
Naked
Single
Linear
Icosahedral
Norovirus
Flaviviruses
Naked or enveloped
Single or double stranded
Linear or circular
Capsid symmetry?
Enveloped
Single
Linear
Icosahedral