Bacteriophages ("Phages")

    Bacteriophages ("bacteria eaters") are viruses that attack bacteria. The name is commonly shortened to "phage". As seen in the electron micrograph, phage comprise a "head" and "tail". The round "head" contains DNA surrounded by a protein coat. Phages attach to the outer membrane of bacteria by means of the thin "tail", and inject DNA into the bacteria. The phage multiply using the bacteria's gene system, which eventually fill and rupture the bacteria, which releases more phage. This has been likened to a tank that enters an auto factory through the loading dock. The tank re-programs the assembly line to make more tanks, which eventually crash through the walls of the factory.
 
    Early biochemical and genetic studies of phage are the foundations of modern molecular biology.