Question

What key features distinguish the lytic from the lysogenic cycle?

Short answer

The key distinctions are that the lytic cycle leads to the destruction of the host cell, and produces viruses immediately, whereas the lysogenic cycle incorporates viral genetic material into the host cell's DNA, allowing the virus to lie dormant until conditions are favorable for it to switch to the lytic cycle.

Step-by-step solution

Defining the Lytic Cycle

In the lytic cycle, after the virus penetrates the cell, it uses the cell's machinery to replicate. Then, it gathers all its parts and forms new viruses. Afterward, the cell lyses (ruptures) and releases these viruses to infect other cells. Key feature of this cycle is the destruction of the host cell.

Defining the Lysogenic Cycle

In the lysogenic cycle, the virus integrates its genetic material into the host's genome. This allows the virus to stay dormant or replicate along with the host's DNA without damaging the cell immediately. When the host cell divides, the viral DNA is passed to the daughter cells. At some point, the virus may switch to the lytic cycle and start producing viruses. Key feature of this cycle is the integration of the viral genetic material into the host cell's genome without immediate destruction of the host cell.

Differentiating the Two Cycles

The main distinctions between the lytic and lysogenic cycles are: 1. The lytic cycle leads to the death of the host cell, but the lysogenic cycle does not (at least not immediately). 2. In the lysogenic cycle, the virus’s genetic material is incorporated into the host cell’s DNA, this does not happen in the lytic cycle. 3. The viruses produced in the lytic cycle are released immediately while in the lysogenic cycle viruses may lie dormant for a while before switching to the lytic cycle.