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Definition

noun, plural: phages

(1) A bacteriophage: a virus capable of infecting a bacterial cell, and may cause lysis to its host cell.

(2) A suffix that means a thing that eats or devours (as macrophage).

Supplement

Bacteriophages or phages have a specific affinity for bacteria. They are made of an outer protein coat or capsid that encloses the genetic material (which can be an RNA or DNA, about 5,000 to 500,000 nucleotides in length). They inject their genetic material into the bacterium following infection. When the phage strain is virulent, all the synthesis of the host's DNA, RNA and proteins ceases. The phage genome is then used to direct the synthesis of phage nucleic acids and proteins using the host's transcriptional and translational apparatus. When the sub-components of the phage are produced, they self-assemble to form new phage particles. The new phages produce lysozyme that ruptures the cell wall of the host, leading to the release of the new phages, each ready to invade other bacterial cells.

Word origin: from Greek phagein (to eat)

Also called: bacteriophage

Related terms:

• Temperate phage
• Tailed phage
• B phage
• Helper phage
• Lambda phage