Bacteriophage φx174

Definition

Bacteriophage φx174 is a type of virus that specifically infects bacteria, particularly Escherichia coli. It is notable for being one of the first viruses to have its genome completely sequenced and plays a significant role in understanding viral genome replication and protein synthesis processes.

5 Must Know Facts For Your Next Test

1. Bacteriophage φx174 has a small circular ssDNA genome consisting of approximately 5,386 nucleotides.
2. This bacteriophage has a simple structure with an icosahedral capsid and no tail, making it unique among phages.
3. φx174 can replicate within E. coli through both lytic and lysogenic cycles, though it primarily follows the lytic cycle.
4. The completion of its genome sequencing in 1977 was a pivotal moment in molecular biology, paving the way for advances in genetic engineering and virology.
5. φx174 is used as a model organism in research for studying DNA replication mechanisms and protein synthesis in viruses.

Review Questions

• How does the structure of bacteriophage φx174 facilitate its replication process in host bacteria?
  • The structure of bacteriophage φx174 features an icosahedral capsid that protects its single-stranded DNA genome during infection. Once it attaches to the surface of E. coli, the viral DNA is injected into the host cell. This structure allows the phage to efficiently utilize the bacterial machinery for replicating its genome and synthesizing proteins necessary for producing new viral particles.
• Compare and contrast the lytic and lysogenic cycles of bacteriophage φx174 and their implications for bacterial populations.
  • In the lytic cycle, bacteriophage φx174 invades a host cell, replicates rapidly, and ultimately causes cell lysis to release new phage particles. This cycle leads to rapid destruction of bacterial cells. In contrast, during the lysogenic cycle, φx174 integrates its DNA into the bacterial genome, where it can remain dormant and replicate along with the host cell's DNA. This can lead to stable infection in bacterial populations over time without immediate cell death.
• Evaluate the impact of bacteriophage φx174's complete genome sequencing on the field of virology and molecular biology.
  • The complete genome sequencing of bacteriophage φx174 marked a significant milestone in virology as it provided a comprehensive understanding of viral genetics and replication mechanisms. This achievement enabled researchers to develop techniques in genetic engineering and molecular biology, leading to advances such as recombinant DNA technology. The insights gained from studying φx174 have also influenced our understanding of more complex viruses and contributed to biotechnology applications, highlighting its importance as a model organism.

Related terms

Single-stranded DNA (ssDNA): A type of nucleic acid that consists of a single strand, which is the genetic material for some viruses, including bacteriophage φx174.

Lytic cycle: The process by which a virus infects a host cell, replicates itself, and ultimately causes the host cell to burst, releasing new viral particles.

Viral replication: The process by which a virus makes copies of itself within a host cell, involving the use of the host's cellular machinery.