Virus

• The systematic study of Virus is called virology.
• A virus is both a living and non living, thus it’s a connecting link between living and non living.
• Viruses may infect all types of organisms; animals, plants, bacteria and archae.
• Dmitri Ivanovsky's discovered in 1892.
• Martinus Beijerinck discovered tobacco virus in 1898.
• Viruses exists in millions, however, characteristics of nearly 5000 viruses is described in science.
• Viruses are found in almost every ecosystem on Earth and are the most abundant type of biological entity.
• Virus particles also known as virions consist of two or three parts: the genetic material made from either DNA or RNA, long molecules that carry genetic information; a protein coat that protects these genes; and in some cases an envelope of lipids that surrounds the protein coat when they are outside a cell.
• The shapes of viruses range from simple helical and icosahedral forms to more complex structures.
• The size of an average virus is about one one-hundredth the size of the average bacterium. Most viruses are too small to be seen directly with an optical microscope. Their size range from 250 to the 20 nm of parvoviruses.
• Viruses are 10 to 1000 times smaller than most bacteria, so they can pass through the pores of filter, from which bacteria cannot pass.
• Viruses cannot be grown on artificial media. They produce only in animal and plant cells or in microorganisms
• Viruses lack metabolic machinery for the synthesis of their own nucleic acid and protein. They depend on the host cell to carry out these vital functions.
• During reproduction in the host cells, viruses may cause disease.
• All viruses are generally resistant to broad range of available antibiotics such as penicillin, streptomycin and others.