Prophage

Definition

A prophage is a bacteriophage genome integrated into the DNA of a bacterial host. It remains dormant until triggered to enter the lytic cycle.

5 Must Know Facts For Your Next Test

1. Prophages are formed during the lysogenic cycle of bacteriophages.
2. The integration of the prophage into the bacterial chromosome is facilitated by specific recombination events.
3. Prophages can confer new properties to the host bacteria through horizontal gene transfer, sometimes providing advantages like toxin production or antibiotic resistance.
4. Environmental triggers such as UV light or stress can induce a prophage to excise from the host genome and enter the lytic cycle, leading to cell lysis.
5. Not all bacteriophages form prophages; only temperate phages have this capability.

Review Questions

• What triggers a prophage to enter the lytic cycle?
• How does a prophage benefit its bacterial host?
• What is the difference between a temperate phage and a virulent phage in terms of their life cycles?

Related terms

Lysogenic Cycle:

A viral replication cycle in which the virus's nucleic acid is integrated into the host cell's genome.

Lytic Cycle:

A viral replication cycle that results in the destruction of the host cell and release of new virus particles.

Temperate Phage: A type of bacteriophage that can choose between a lytic and lysogenic pathway for reproduction.