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SIZE - MEASURED IN NANOMETERS
SUB-LIGHT MICROSCOPIC
4 MAJOR GROUPS
1. ANIMAL
2. PLANT
3. BACTERIAL
4. VIRUSES OF EUCARYOTIC MICROBES
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FUNGI AND PROTISTA
COMMON CHARACTERISTICS OF VIRUSES
• 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
• VARIABILITY OF VIRUSES
– TYPE OF NUCLEIC ACID
• CIRCULAR, LINEAR, DS, SS, IN SEGMENTS
– MORPHOLOGY OF CAPSID
• N SPIKES – NEURAMINIDASE
• H SPIKES – HEMAGGLUTININ
• H1N1 – 1918 – FLU VIRUS
– Killed 40 – 50 million people world wide
• H5NI – TODAYS BIRD FLU
• Indonesia - killed 7 people
• Swine flu virus
• IS THERE EVER ANYTHING ELSE IN THE
CORE IN ADDITION TO THE 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