What is the Difference Between Lytic and Lysogenic Cycle of Bacteriophage?

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The main difference between the lytic and lysogenic cycles of bacteriophages lies in their influence on the host cell. Bacteriophages are viruses that infect bacteria. Here are the key differences between the two cycles:

Lytic Cycle:

  • Involves the reproduction of viruses using a host cell to manufacture more viruses.
  • The viruses burst out of the cell, killing the host cell in the process.
  • DNA replication of the virus takes place independently from the host DNA replication.
  • Symptoms of viral replication are evident.
  • Occurs within a short period of time.
  • An example of a lytic bacteriophage is T4, which infects E. coli found in the human intestinal tract.

Lysogenic Cycle:

  • Involves the incorporation of the viral genome into the host cell genome.
  • The host cell continues to survive and reproduce, with the virus being reproduced in all of the cell's offspring.
  • DNA replication of the virus takes place along with the host DNA replication.
  • Symptoms of viral replication are not evident.
  • Takes more time compared to the lytic cycle.
  • Genetic recombination in the host bacterium is not allowed.
  • An example of a bacteriophage known to follow both the lytic and lysogenic cycles is the phage lambda.

In summary, the lytic cycle involves the rapid production of viruses that ultimately destroy the host cell, while the lysogenic cycle allows the host cell to continue living and reproducing, with the virus replicating alongside the host genome.

Comparative Table: Lytic vs Lysogenic Cycle of Bacteriophage

The lytic and lysogenic cycles are two different modes of viral reproduction in bacteriophages, which are viruses that infect bacteria. Here is a table comparing the key differences between the two cycles:

Feature Lytic Cycle Lysogenic Cycle
Description The virus takes control of a host cell and uses it to produce viral progeny, eventually killing the host cell. The virus incorporates its DNA into the host cell's DNA, becoming dormant and allowing the host cell to reproduce while carrying the viral genome.
Effect on Host Cell Host cell is broken open (lysed) and destroyed after immediate replication of the virion. Host cell survives and reproduces, passing the viral genome to subsequent generations.
Latency Period No latency period. A period of latency, during which the viral genome is incorporated into the host genome and no viral replication occurs.
Symptoms of Viral Replication Evident. Not evident.
Genetic Recombination in Host Bacterium Allowed. Not allowed.
DNA Replication of Virus Takes place independently from the host DNA replication. Takes place along with the host DNA replication.
Occurrence Comparatively more common. Less common.

In summary, the lytic cycle involves the virus taking control of a host cell, replicating, and then lysing the host cell, while the lysogenic cycle involves the virus incorporating its DNA into the host cell's DNA, remaining dormant, and allowing the host cell to reproduce while carrying the viral genome.