VIRUSES

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VIRUSES
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• SIZE - MEASURED IN NANOMETERS
• SUB-LIGHT MICROSCOPIC
• 3 MAJORS GROUPS
• ANIMAL
• PLANT
• BACTERIAL
• VIRUSES OF EUCARYOTIC MICROBES
• FUNGI AND PROTISTA
• COMMON CHARACTERISTICS OF VIRUSES

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• ALL ARE OBLIGATE INTRACELLULAR PARASITES
• ALL HAVE NO INDEPENDENT METABOLIC PATHWAYS FOR
  ENERGY SYNTHESIS
• THEY ALL POSSESS ONLY ONE NUCLEIC ACID - RNA OR
  DNA NEVER BOTH
• THEY ALL HAVE A COMMON BASIC STRUCTURE SEEN IN
  1942 WITH EM

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• VARIABILITY OF VIRUSES
• TYPE OF NUCLEIC ACID
• CIRCULAR, LINEAR, DS, SS, IN SEGMENTS
• MORPHOLOGY OF CAPSID

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POLYHEDRAL - ICOSAHEDRON
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HELICAL
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ENVELOPED VIRUSES
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• IS THERE EVER ANYTHING ELSE IN THE CORE IN
  ADDITION TOTHE NUCLEIC ACID?
• INTRACELLULAR REPLICATION
• CLASSIFICATION OF VIRUSES - INTERNATIONAL
  COMMITTEE ON TAXONOMY OF VIRUSES (ICTV) - 1966
• TAXONOMIC LEVELS
• ORDER, FAMILY,GENUS,SPECIES
• NUCLEIC ACID
• MORPHOLOGY
• PRESENCE OR ABSENCE OF AN ENVELOPE
• STRATEGY OF REPLICATION