General Characters Of Viruses

  1. They do not occur free in nature but act as obligate intracellular parasite.
  2. They are extreme microscopic structure which can only be seen by electron microscope.
  3. Mainly the size ranges from 100-2000 millimicron.
  4. They cannot be filtered by bacterial filters.
  5. The genetic material is either DNA or RNA which occurs in the form of single molecule and can be single or double stranded.
  6. A single virus particle is known as virion which lacks functional autonomy.
  7. They lack their own enzyme system but interact with the host enzyme system and synthesize new virus particles. Thus they have a master and slave relationship.
  8. Outer capsid of virus is proteinaceous and harmless and provide cellular specificity to the virus.
  9. They are intracellular obligate parasite and cannot be cultured on artificial culture media.
  10. All animal and plant viruses have a narrow host range while others show a broad host range.
  11. They show replication
  12. They are highly infectious and spread disease very quickly.
  13. They show special kind of pathogenicity i.e. they cause disease at particular temperature. Most of virus become inert at 56 – 69 C (for 30 minutes).
  14. They are haploid.
  15. They are unaffected by antibiotics.
  16. They show life between 5 -9 pH.
  17. They remain active for a long time when kept in 50% glycerol solution.
  18. The extract of virus become inert at high pressure and high sound frequency.
  19. They get precipitated with ethyl alcohol and acetone.
  20. They can be inserted by treatment with ultraviolet rays, pyridine, urea and hydrogen peroxide.
  21. They can be crystallized.
  22. They show response towards temperature, radiation and chemical substances.
  23. They lack cell wall, nucleus, protoplasm and cell organelles.

Gaurav Singh

Editor in Chief Medical Microbiology & Recombinant DNA Technology (RDT) Labs - RDT Labs Magazine

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