Virology is the study of viruses, which are submicroscopic particles that contain genetic material within a protein coat. It focuses on virus structure, classification, evolution, infection of host cells, interaction with host physiology and immunity, diseases caused, isolation and culture techniques, and application in research and therapy. Viruses can be classified according to the nucleic acid type that makes up their genome and how they replicate - including DNA viruses, RNA viruses, and reverse transcribing viruses. Major branches of virology include classification of animal viruses, plant viruses, and bacteriophages.

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VIROLOGY
Presented by:
Khushbu’s Microbiology

2.  Virology : known as a study of
viruses – submicroscopic, parasitic
particles of genetic material
contained in a protein coat & virus-
like agent
 Focuses on : structure, classification
and evolution, their ways to infect
and exploit host cells for
reproduction, their interaction with
host organism physiology and
immunity, the diseases they cause,
the techniques to isolate and culture
them, and their use in research and
therapy.
 Virology is a subfield
of microbiology.
 A major branch of virology is virus
classification.
DEFINATION

3.  Viruses can be classified according to the
host cell they infect:
 animal viruses,
 plant viruses,
 bacteriophages (viruses infecting bacteria,
which include the most complex viruses).
CLASSIFICATION

4.  The most useful and most widely used classification system distinguishes
viruses according to the type of nucleic acid
 Nucleic Acid as genetic material and the viral replication method they
employ to coax host cells into producing more viruses:
 DNA viruses :
01 double-stranded DNA viruses :
02 single-stranded DNA viruses
 RNA viruses :
O1 positive-sense single-stranded RNA viruses,
02 negative-sense single-stranded RNA viruses
03 double-stranded RNA viruses
 reverse transcribing viruses
01 double-stranded reverse-transcribing DNA viruses
02 single-stranded reverse-transcribing RNA viruses including retroviruses
DNA & RNA based Virus
Classification

5.  Animal viruses are viruses that infect animals.
 Viruses infect all cellular life and although
viruses infect every animal, plant, fungus and
protist species, each has its own specific range of
viruses that often infect only that species.
Animal
Virus

6.  Plant viruses :
 viruses that affect plants.
 obligate intracellular parasites
 Do not have the molecular machinery
to replicate without a host.
 Pathogenic to higher plants.
 Pepper mild mottle virus
 (PMMoV) is a plant
pathogenic
virus

7.  Bacteriophage :
 informally as a known as a phage
 infects and replicates within:
bacteria and archaea.
 Composed:proteins encapsulate
a DNA or RNA genome,
 Structures:
simple
or elaborate.
 The structure of a typical
myovirus bacteriophage

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