characteristics of virus

 

Virus is obligate intracellular, non- filterable, ultra-microscopic parasite. Which require living animal, plant or bacterial cell for their reproduction. It has both characters, non- living ( outside the body / cell ) Living ( in the body )

           It has some unique features such as:-

       ① It has only one nucleic acid either DNA or RNA.

       ② It does'nt contain energy generating enzyme ATP.

       ③ Like inorganic matters, it can be cry stallised.

       ④ It passes through eclipse phase during invasion into host cell.

       ⑤ It is capable of bringing change in metabolic behavior of infected cell.

       ⑥ Some virus produce inclusion bodies ( group of viruses in cytoplasm ) in infected cell help in their diagnosis.

       ⑦ Infected cell produce interferon ( A type of chemical which protect from infection to another cell ) which protects non- infected cell from viral invasion.

       ⑧ For culture of virus living cell are necessary.

       ⑨ They produce cytopathic affect in the cell culture tissue.

      ⑩ Some virus may produce tumour are known as oncogenic viruses.

      ⑪ They don't multiply by binary fission.

      ⑫ They are small infecting agent (> soonm in diameter. )

      ⑬ They are antigenic and evoke production of antibody.

      ⑭ Immunity produced after infection is usually for the short time but some produce life long immunity such as small pox.

    ⑮ There are no staining materials used to visualise viruses.

    ⑯ Viruses don’t infect Fungi but infect bacteria.

    ⑰ Viruses are not sensitive to antibiotic.

    ⑱ Some viruses shows envelope which is ether sensitive.

    ⑲ Individual virus particle was previously known as elementary body.

    ⑳ Lipid of viral antigen is host antigen but protein of the envelope is viral antigen.