VIRUS, CHARACTERS OF VIRUS ( did you know )??????

Virus

• Study of virus is called virology.
• Virus was discovered by Russian scientist Ivanovsky  in the year 1892 ( During the test of Mosaic disease in the tobacco)
• In the nature, there are ultra microscopic particle know as viruses.
• It has both the characters of living and non living, so it is a connecting link between living & non living.
• Dr. Stanley first isolated the virus causing mosaic disease in tobacco in the from of crystals.

Characters of virus

• They became active inside a living cells.
• Nucleic acid replicate themselves and they reproduce rapidly.
• They cause disease like bacteria & fungi.                                                                                                                                                                                                                                                              According to parasitic nature, virus is of three types----
• Plant virus-RNA is present as its nucleic acid.
• Animal virus-DNA or something RNA is found in it.
• Bacteriophage-They depend only on bacteria. They kill the bacteria. DNA is found in them. Example-T-2 phage 

• In man virus cause disease like mumps, chicken pox, hepatits, polio, AIDs and Herpes.
• HIV often change its shape due to the presence of an enzyme reverse transcriptase.
• The enzyme integrase produced by virus allow the integration of HIV-DNA into the host cell DNA.
• EBOLA is virus, causes ebola fever. Fruit Bats are the natural host of this virus, first outbreak in West Africa.
• Bacteriophages:Bacteriophages are those virus which infect the bacteria, Example-Tobacco mosaic virus. 

Note:Those viruses in which RNA is found as genetic material are called Retrovirus.

(written by the book Lucent's)