2. 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

3. 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

8. VARIABILITY OF VIRUSES –TYPE OF NUCLEIC ACID CIRCULAR, LINEAR, DS, SS, IN SEGMENTS –MORPHOLOGY OF CAPSID

14. 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

15. IS THERE EVER ANYTHING ELSE IN THE CORE IN ADDITION TO THE NUCLEIC ACID? INTRACELLULAR REPLICATION

17. 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