T4 Phage

Definition

The T4 phage is a type of bacteriophage, which is a virus that infects bacteria, specifically Escherichia coli. This complex virus is known for its icosahedral head and long tail structure, allowing it to efficiently inject its genetic material into host cells. The T4 phage follows a lytic life cycle, where it takes over the host's machinery to produce new phage particles, ultimately leading to the lysis or destruction of the bacterial cell.

5 Must Know Facts For Your Next Test

1. The T4 phage has a double-stranded DNA genome that is about 169 kilobases in length.
2. It attaches to E. coli cells using specific receptors on the bacterial surface, allowing for targeted infection.
3. Once inside the host cell, the T4 phage can produce up to 300 new phage particles before causing the cell to burst.
4. T4 phages are often used in molecular biology and genetic engineering due to their well-characterized genome and replication mechanisms.
5. Research on T4 phages has contributed significantly to our understanding of DNA packaging and viral assembly processes.

Review Questions

• How does the structure of the T4 phage facilitate its infection process in bacterial cells?
  • The structure of the T4 phage is key to its infection process. It has an icosahedral head that contains its genetic material and a long tail with tail fibers that are essential for attachment to specific receptors on E. coli cells. Once attached, the tail contracts, and the phage injects its DNA into the bacterial cell, allowing it to hijack the host's machinery for replication.
• Compare and contrast the lytic cycle of the T4 phage with the lysogenic cycle of other bacteriophages.
  • The lytic cycle of the T4 phage involves direct takeover of the host cell's machinery to produce new phage particles, leading to cell lysis and release of these new viruses. In contrast, lysogenic cycles involve integration of the viral genome into the host's DNA, where it can remain dormant and replicate along with the host until conditions trigger it to enter a lytic phase. This fundamental difference defines how these two types of bacteriophages interact with their hosts.
• Evaluate the implications of T4 phage research on advancements in genetic engineering and molecular biology.
  • Research on T4 phages has significant implications for advancements in genetic engineering and molecular biology. The detailed understanding of its genome and replication mechanisms has paved the way for techniques such as gene cloning and synthetic biology. Moreover, T4 phages serve as powerful tools for studying viral infections and host interactions, contributing to broader insights in virology and potential therapeutic applications such as phage therapy for antibiotic-resistant bacteria.

Related terms

Lytic Cycle: The phase of viral replication in which the virus hijacks the host cell's machinery to produce new viruses, resulting in cell lysis.

Bacteriophage: A type of virus that specifically infects bacteria, utilizing their cellular machinery for replication.

Genetic Material: The DNA or RNA that carries the genetic information necessary for the virus to replicate and produce proteins within the host cell.