Lytic cycle

Lytic Cycle

The lytic cycle is one of the two main life cycles of bacteriophages, the other being the lysogenic cycle. In the lytic cycle, the phage replicates within a bacterium, ultimately leading to the lysis, or destruction, of the host cell and the release of new phage particles.

Diagram of the lytic cycle of a bacteriophage

Attachment

The lytic cycle begins with the attachment of the phage to the surface of the bacterial cell. This is a highly specific interaction, where the phage recognizes and binds to specific receptors on the bacterial surface.

Penetration

After attachment, the phage injects its genetic material into the host cell. The phage's capsid remains outside the bacterium, while the DNA or RNA enters the host.

Biosynthesis

Once inside, the phage DNA takes over the host's cellular machinery to synthesize phage components. The host's ribosomes, enzymes, and nucleotides are used to produce phage proteins and replicate the phage genome.

Maturation

During maturation, the newly synthesized phage components are assembled into complete phage particles. This includes the assembly of the phage head, tail, and tail fibers.

Lysis

The final stage of the lytic cycle is the lysis of the host cell. The phage produces lysozyme or other enzymes that degrade the bacterial cell wall, causing the cell to burst and release the newly formed phages into the environment.

Significance

The lytic cycle is significant in the context of bacterial infections and phage therapy. It is a mechanism by which phages can control bacterial populations and has potential applications in treating antibiotic-resistant bacterial infections.

Related Pages

• Bacteriophage
• Lysogenic cycle
• Viral replication
• Phage therapy