Final answer:
The lytic cycle involves the destruction of the host cell by the bacteriophage to release new viral particles, while the lysogenic cycle involves integration of the phage DNA into the host's genome, with the potential to reactivate into the lytic cycle under stress conditions.
Step-by-step explanation:
The lytic and lysogenic modes are two distinct reproductive cycles of bacteriophages, which are viruses that infect bacteria.
The Lytic Cycle
In the lytic cycle, a bacteriophage attaches to a host cell and injects its DNA. The phage DNA then commandeers the host's cellular machinery to replicate the phage's components and assemble new phage particles. This process culminates in the lysis, or bursting, of the host cell, releasing the newly created bacteriophages into the environment to infect other cells. An iconic example of a lytic bacteriophage is T4, which targets Escherichia coli.
The Lysogenic Cycle
Conversely, in the lysogenic cycle, the phage DNA becomes integrated into the host cell's genome, forming a prophage. This prophage is replicated along with the host cell's DNA and passed on to subsequent generations of cells. Prophages can remain dormant but may be induced to enter the lytic cycle under stress conditions like starvation or exposure to toxic chemicals, leading to the production of new phages and the destruction of the host cell. An example of a lysogenic bacteriophage is the lambda virus, which also infects E. coli.