Multiplication of Virulent phage: The lytic cycle
* The lytic cycle is a phage replicative cycle that culminates in the death of the host cell
* The lytic cycle produces new phages and lyses (breaks open) the host’s cell wall, releasing the progeny viruses
* A phage that reproduces only by the lytic cycle is called a virulent phage
* Bacteria have defenses against phages, including restriction enzymes that recognize and cut up certain phage DNA.
The lytic cycle has the following steps:
* Adsorption- Anchoring of bacteriophage to the bacterial cell wall with the help of tails fibres.
* Penetration- The phage DNA gets injected into bacteria.
* Replication and synthesis- The bacterial DNA is disrupted and the viral genome takes charge of bacterial machinery. It starts making proteins required for replication and other structural proteins.
* Assembly- Phage components are assembled into new viral particles.
* Lysis and release- Bacterial cells are lysed and new viral particles are liberated to infect other cells.
