Compare and contrast the lysogenic and lytic cycles of the bacteriophage. Be sure to be specific about the main differences between the two cycles.
The correct answer and explanation is:
Correct Answer:
The lysogenic and lytic cycles are two distinct methods by which bacteriophages infect and replicate within bacterial cells. The key difference between the two lies in how the viral genetic material interacts with the host cell.
Explanation:
The lytic cycle is a replication process that results in the immediate destruction of the host bacterial cell. It begins when the bacteriophage attaches to the bacterial cell and injects its DNA into the host. Once inside, the viral DNA takes control of the host’s cellular machinery to produce new viral components. These components include the viral genome and proteins, which are then assembled into new viruses. Once assembly is complete, the host cell is lysed, or broken open, releasing new bacteriophages to infect other cells.
In contrast, the lysogenic cycle involves the integration of the viral DNA into the host’s chromosome. This integrated viral DNA is called a prophage. During this cycle, the bacteriophage DNA remains dormant within the host genome and is replicated along with the host cell’s DNA during normal cell division. As a result, each new daughter cell contains the prophage. The virus does not immediately harm the host cell. However, environmental triggers such as radiation or stress can cause the prophage to excise from the host genome and enter the lytic cycle, resulting in the production of new viruses and lysis of the host cell.
The main difference between the two cycles lies in the immediacy of viral replication and cell destruction. The lytic cycle leads to rapid production of viruses and cell death, while the lysogenic cycle allows the virus to persist in the host without killing it immediately. This allows the virus to spread silently through many generations of cells before becoming active. Therefore, the lysogenic cycle contributes to long-term viral persistence, whereas the lytic cycle focuses on short-term viral multiplication.