False-colour transmission electron micrograph (TEM) of a field of unidentified bacteriophages: bacteriophages are viruses that only infect bacteria. They lack any reproductive machinery & rely on the apparatus of bacteria in order to replicate. They do so by attaching to the cell wall using the spidery tail fibres faintly visible here. The ribbed tail, a contractile sheath (the orange rod-like body - the head appears vaguely icosahedral in shape), contracts to inject the contents of the head, the genetic material (DNA) into the cell. The genetic apparatus of the host is commandeered & within 30 minutes progeny fill the cell. Magnification: X 14,700 at 35mm size.