Temperate Phage

Definition

A temperate phage is a type of bacteriophage that can choose between two different reproductive cycles: the lytic cycle, where it replicates and causes the host cell to burst, or the lysogenic cycle, where its genetic material integrates into the host genome and remains dormant. This dual lifestyle allows temperate phages to persist in environments where host bacteria are scarce, providing flexibility in their survival strategy.

5 Must Know Facts For Your Next Test

1. Temperate phages can remain inactive for extended periods as prophages within bacterial genomes, potentially influencing bacterial traits through horizontal gene transfer.
2. When environmental conditions become unfavorable, a prophage can be induced to enter the lytic cycle, leading to the production of new phage particles.
3. The ability of temperate phages to integrate into host genomes allows them to contribute to genetic diversity in bacterial populations.
4. Temperate phages can play a significant role in shaping bacterial evolution by facilitating gene exchange among different strains of bacteria.
5. Some temperate phages have been utilized in biotechnological applications, including phage therapy, which targets specific bacterial infections.

Review Questions

• Compare and contrast the lytic and lysogenic cycles in terms of their impact on the host cell.
  • The lytic cycle results in the destruction of the host cell as the bacteriophage replicates and eventually causes the cell to burst, releasing new viral particles. In contrast, the lysogenic cycle allows the temperate phage to integrate its DNA into the host genome as a prophage, which can replicate along with the host's DNA without immediately harming the cell. This means that while lytic infections rapidly kill host cells and produce new phages, lysogenic infections can persist over time without destroying the host, allowing for potential future activation.
• Discuss how temperate phages can influence bacterial genetic diversity and evolution.
  • Temperate phages contribute to bacterial genetic diversity through mechanisms like horizontal gene transfer. When a temperate phage integrates into a bacterial genome as a prophage, it can carry genes that confer advantageous traits, such as antibiotic resistance or virulence factors. When this prophage is excised and enters the lytic cycle, it can package these genes into new phage particles and introduce them into other bacteria during subsequent infections. This process enhances genetic variation and can drive evolutionary changes in bacterial populations.
• Evaluate the potential applications of temperate phages in biotechnology and medicine.
  • Temperate phages have significant potential applications in biotechnology and medicine, particularly in developing phage therapy for bacterial infections. By targeting specific pathogens without harming beneficial bacteria, temperate phages offer a promising alternative to traditional antibiotics, especially amid rising antibiotic resistance. Additionally, their ability to integrate into bacterial genomes can be harnessed for genetic engineering, enabling scientists to create bacteria with desirable traits for industrial processes. Overall, temperate phages represent a versatile tool for advancing both therapeutic approaches and biotechnological innovations.

Related terms

Lytic Cycle: The lytic cycle is the process in which a bacteriophage replicates within a host cell, leading to the cell's lysis and the release of new viral particles.

Lysogenic Cycle: The lysogenic cycle involves the integration of a phage's DNA into the bacterial genome, allowing it to replicate along with the host's DNA without causing immediate harm.

Prophage: A prophage is the dormant form of a temperate phage when its DNA is integrated into the bacterial chromosome during the lysogenic cycle.