Lysogen

Definition

A lysogen is a bacterial cell that harbors a prophage, which is a viral genome integrated into the host DNA. The prophage can remain dormant until it is induced to enter the lytic cycle.

5 Must Know Facts For Your Next Test

1. Lysogens are formed when a bacteriophage infects a bacterium and integrates its DNA into the host genome.
2. Prophages in lysogens can be triggered to enter the lytic cycle by environmental stressors such as UV light or certain chemicals.
3. Lysogenic conversion can occur, where the prophage confers new properties to the bacterial host, such as toxin production.
4. The lysogenic cycle allows phages to persist in the host without killing it, providing a survival advantage under certain conditions.
5. Lysogens can revert to being non-lysogenic if the prophage excises itself from the bacterial chromosome.

Review Questions

• What triggers can cause a prophage in a lysogen to enter the lytic cycle?
• How does lysogenic conversion affect bacterial virulence?
• Describe the difference between a lysogen and a bacterium undergoing lytic infection.

Related terms

Bacteriophage: A virus that infects bacteria.

Prophage: Viral DNA that is integrated into the host's genome.

Lytic Cycle: A viral reproductive cycle resulting in host cell lysis and release of progeny viruses.