Bacteriophages are also known as bacterial Viruses or phages .They are the viruses that Infect bacteria. phages are first discovered independently by Frederick w.Twort in great britain C 1915) and Felix d’ Herelle In France (1917). Like all viruses, phages are Viruses that consist of a core of genetic material surrounded by a protein coat Or capsid.
The phage genomemay be DNA or RNA, single or doublestranded, circular or linear, generally present as a single copy. Morphologically varies from simple, Icosahedral and filamentous phage to more complex tailed phages with 9n Icosahedral head.
They are obligate intracellular parasites that multiply inside bacteria by making use of some or all of the host biosynthetic machinery.