T-bacteriophage. Coloured transmission electron micrograph (TEM) of a single bacteriophage (phage) virus of Escherichia coli. At upper centre is the protein head of the phage which contains the virus's genetic material (DNA). The narrow red collar beneath the head acts as a syringe to insert virus DNA into a host cell when attacking E. coli bacteria. Attached to the collar are several green-coloured tail fibres which help the virus to attach itself onto the bacterial cell. T- phages parasitize only E coli, The virus DNA is inserted into the bacterial cell and instructs the bacteria to reproduce more phages. Magnification: x135,000 at 5x7cm size.