General Properties of Viruses
General Properties of Viruses
General Properties of Viruses
Viruses
II MBBS
Dr Ekta Chourasia
Microbiology
General Properties
Obligate intracellular parasites
Contain only one type of nucleic acid, either
DNA or RNA
Do not possess cellular organization
Lacks enzymes necessary for protein & NA
synthesis
Depends on host cell machinery for replication
Causes a large no. of human diseases ranging
from minor ailments like common cold to
terrifying diseases such as rabies, HIV etc.
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General Properties
size, structure, shape,
chemical properties, resistance
Replication
Hemagglutination
Cultivation
Viral assay
Viral infections: virus-host interactions
Morphology
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Morphology - Size
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E
L
E
C
T
R
O
N
Nucleic acid
Capsid
Envelope
Peplomer
Size in nanometers
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M
I
C
R
O
S
C
O
P
E
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4. Mature
Capsid
1. Protomers
2. Capsomers
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3. ProCapsid
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Capsomers
This
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Icosahedral (cubical)
Helical
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Resistance
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Viral Replication
Stages in virus replication begin when virions infect cells
Attachment/
Adsorption
Penetration
Uncoating
Biosynthesis
Maturation &
Assembly
Release
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Lysis of
Endosome
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Viral Replication
phase from the stage of
penetration till the appearance of mature
daughter virions, the virions cannot be
detected inside the host cell.
Eclipse
http://www.liquidjigsaw.com/animation/anim5.htm#
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Viral Hemagglutination
Hemagglutination
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Virus Culture
Embryonated Egg
Cell Lines/
Tissue cultures
Primary
Diploid/ Secondary
Continuous
Animal inoculation
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Suckling mice
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Viral Assay
2.
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Viral Assay
Assay of Infectivity:
Quantitative assays
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