• Viruses are sub-microscopic obligate intracellular parasites that replicate only in living susceptible cells and possess a central core made up of one nuclei acid, either RNA or DNA never both


  • The complete infective virus particles (i.e. capsid enclosing the nucleic acid) which are INERT CARRIERS of the genome (do not grow) are called VIRIONS



“A piece of bad news wrapped up in a protein”