Classification of Viruses
Viruses are classified in the following ways:
-- Genome Structure. (This is the main way viruses are classified).
---- DNA viruses (all are double-stranded except Parvoviriridae and Hepadnaviridae)
---- RNA viruses (all are single-stranded except Reoviridea)
-- Shape. Isohedrical, Rod shape, Irregular, or Complex
-- Enveloped or Naked
-- Taxonomy. Informally grouped prior to Family
-- Nomenclature. Uses Family and Genus
-- Species. Includes the common name based on the disease it is associated with and always ends the word "virus". Rabies virus, Polio virus, etc.
Major Characteristics of Bacteriophages
-- Normally complex in shape and are naked viruses
-- Phages can be productive, extruded, or temperate in nature.
-- Has a host of range factors
----attachment protein is needed to bind to a specific receptor site on the bacteria. Normally on the cell wall, but occasionally on the flagella or pilli.
Steps of Lytic Replication
-- Replication of animal viruses is the same basic replication pathwa as bacteriophages.
1) Presence of envelopes around some viruses
2) Eukaryotic nature of animal cells
3) Lack of cell wall in animal cells
-- Assembly and Release of Animal Viruses
----Most RNA viruses develop soley in the cytoplasm
---- Number depends on type of virus and size and initial health of the host cell
---- Enveloped viruses cause persistant infections
---- Naked viruses released by exocytisis may cause lysis and death of the host cell