• SIZE - MEASURED IN NANOMETERS
• SUB-LIGHT MICROSCOPIC
• 4 MAJOR GROUPS
1. ANIMAL
2. PLANT
3. BACTERIAL
4. VIRUSES OF EUCARYOTIC MICROBES• 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