history of virus discovery

A virus is a microscopic parasite that infects a cell-sized biological organisms. Viruses can only reproduce in living material to invade and take advantage of living cells because the virus does not have the equipment provider to reproduce itself. In the host cell, viruses are obligate parasites and outside its host to become impotent. Usually the virus contains a small amount of nucleic acid (DNA or RNA, but not a combination of both) are shrouded in a kind of protective material composed of proteins, lipids, glycoproteins, or a combination of all three. Both viral genome encodes a protein that is used to contain genetic material or proteins required in the life cycle. The term virus usually refers to particles that infect cells of eukaryotes (multicellular organisms and many types of single-cell organisms), while the term bacteriophage or phage is used for species that attack the cell types of prokaryotes (bacteria and other organisms that are not core cell) . Viruses are often debated status as a living being because he is unable to perform the biological function freely. Because of its distinctive characteristics of these viruses are always associated with certain diseases, both in humans (eg influenza virus and HIV), animals (eg bird flu virus), or plants (eg tobacco mosaic virus / TMV)