In appearance and function, the virus known as T4 bacteriophage resembles nothing so much as a miniature hypodermic syringe, highly specialized for the sole task of injecting its genome into a host bacterium. Once inside, the viral genes co-opt the hosts cellular machinery to build an army of bacteriophages that will, in turn, infect other bacteria. The T4 bacteriophages cell-puncturing device is an insidious hollow molecular needle through which its DNA is injected. To aid penetration of the host cell, the cell-puncturing device is equipped with three bulbous enzymatic domains that digest the cell wall. Once injected, the viral DNA is free to work its mischief. The image is a digital computer model based on real molecules. Magnification: 35 million times at 7"x7" print size.