False colour transmission electron micrograph shadowed of a T bacteriophage a virus that infects only bacteria in this case only Escherichia coli Phages lack any reproductive machinery rely on the apparatus of bacteria in order to replicate They do so by attaching to the cell wall of the bacterium using the spidery tail fibres visible here The tail is a contractile sheath which contracts injecting the contents of the head the genetic material DNA into the cell The genetic apparatus of the host is commandeered within minutes progeny fill the cell Magnification X at mm size Original is bw print m
