Index >> Bacteriophages - Part Two >> Life Cycle of Lambda λ - Lytic Cycle, Lysogenic Cycle

Life Cycle of Lambda λ - Lytic Cycle, Lysogenic Cycle
The phage DNA on entering the host cell may sometimes immediately multiply and enter the lytic cycle. During this cycle the phage genes are expressed and the phage DNA replicated, leading to the production of many phage particles.

This part of the life cycle is virulent, or intemperate. The virus exists in the viron form, with a DNA core in a protein coat (head) and a tail.

In the prophage condition the virus exists in harmony with the host cell and in non infectious. Since the lambda phage normally exists in this condition, it is called a temperate phage. Bacteria containing prophages are called lysogenic bacteria.

Viruses whose chromosomes become prophages are called lysogenic viruses. The prophage can be caused to enter the lytic cycle by inducing agents such as ultra violet light) X-rays and mitomycin C. This process is called induction, and results in the release of the prophage from the bacterial chromosome.