Prophage

Definition

A prophage is a bacteriophage genome that has been integrated into the DNA of a bacterial host. It remains dormant within the host's genome until it becomes induced to enter the lytic cycle.

5 Must Know Facts For Your Next Test

1. A prophage can switch from a lysogenic to a lytic cycle under certain conditions, such as stress or damage to the host cell.
2. Prophages contribute to horizontal gene transfer, potentially providing new traits to bacterial hosts.
3. The integration of prophage DNA into the bacterial genome is catalyzed by an enzyme called integrase.
4. Prophages can carry genes that confer advantages like antibiotic resistance or toxin production to their bacterial hosts.
5. Induction of a prophage involves excision from the bacterial chromosome and entry into the lytic replication cycle.

Review Questions

• What triggers a prophage to switch from the lysogenic cycle to the lytic cycle?
• How does a prophage integrate into the bacterial host genome?
• What benefits can prophages provide to their bacterial hosts?

Related terms

Lysogenic Cycle: A viral replication cycle in which the virus integrates its DNA into the host genome and replicates along with it without causing immediate lysis.

Lytic Cycle: The active viral replication process that results in the destruction of the host cell and release of new viral particles.

Bacteriophage: A type of virus that infects bacteria, often used in molecular biology research due to its specificity and versatility.