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What is T4 Bacteriophage?
T4 bacteriophage, also known as Escherichia virus T4, is a virus that infects the bacterial species Escherichia coli only. It has double stranded DNA. It belongs to the subfamily Tevenvirinae and family Myoviridae. It is one of the seven E. coli phages, the others being T1, T2, T3, T5, T6 and T7. It follows a lytic life cycle.
T4 Bacteriophage Structure
- It is a large virus that ranges in size from 90 nm in width to 200 nm in length.
- The body of the virus is divided into head, tail and long tail fibres.
- The DNA genome is about 169 kbp long that encodes for 298 proteins.
- The genetic material is packed in an icosahedral head that is also known as a capsid.
- The tail of the phage is hollow to facilitate the passage of nucleic acid at the time of infection.
- The presence of tail fibres is the characteristic feature of the family that helps in recognition and attachment to the host.
- The three parts, i.e., the head, tail and the long tail fibres are first synthesised independently before they join together to form a mature phage.
Reproduction
Lytic life cycle is the process where a phage enters into the host, takes over their replication machinery and destroys the host cell to complete their life cycle. In T4 bacteriophages, the lytic cycle takes place at a temperature of 37℃ in about 30 minutes.
The T4 bacteriophage enters the host and starts dividing into progeny phages at a fast rate. Once they reach a certain number of progeny phages, the host cell is lysed and the phages are released for infecting new host cells.
T4 bacteriophage bursts the host cells after reaching a number of 100-150 progeny.
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Also Read:
- Bacteriophage: Definition, Structure, Examples and Life Cycle
- Explore the Differences between Retrovirus and Bacteriophage
- MCQs on Bacteriophage for NEET 2022
- What Are Viruses? Discover the Classification and Properties
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