Lifecycle of virus

• Viruses are obligate intracellular parasites.
• Viruses must gain entry into target cells and usurp the host cellular machinery to produce a progeny virus.
• The multiple steps involved in the virus propagation occurring inside cells are collectively termed the “virus life cycle.”
• After entering the cell and localizing to an intracellular milieu, the virus sheds its capsid, transcribes its RNA, translates its RNA to the viral proteins, replicates its genome, assembles the viral components, and finally exits from the cell.
• The multiple steps involved in the virus propagation occurring inside cells are collectively termed the “virus life cycle.” The virus that invades bacteria are known as bacteriophages.
• Capsid of most of the phages have complex structure, consisting of an isohedral head (Containing DNA or RNA) bound to a helical tail which may have a hexagonal base plate with protruding protein tail fibers for attachment to a host cell.