Bacteriophage on bacterium. Computer illustration of a bacteriophage virus particle (virion, centre) on a bacterium (bottom). A bacteriophage, or phage, is a virus that infects bacteria. It consists of an icosahedral (20-sided) head (centre), which contains the genetic material, DNA (deoxyribonucleic acid), a tail (cylinder) and tail fibres (leg-like), which fix it to a specific receptor site on the bacterium. The bacteriophage then injects its DNA into the host bacterium, where it multiplies to create new virus particles (virions), before the cell ruptures and releases the new viruses. |