Lytic cycle vs lysogenic: Lytic cycle produces virions until the host cell lyses; Lysogenic cycle integrates into the genome as provirus or prophage and remains dormant until stress activates it.

Lytic cycle vs lysogenic: Lytic cycle produces virions until the host cell lyses; Lysogenic cycle integrates into the genome as provirus or prophage and remains dormant until stress activates it.

• A. Lytic cycle produces virions until cell lyses; Lysogenic cycle involves integration and dormancy until stress activates it
• B. Lytic cycle involves dormancy and integration; Lysogenic cycle produces virions immediately
• C. Both cycles immediately lyse the host
• D. Lysogenic cycle ends in cell death without dormancy

Answer: (A)

The key idea here is understanding the two phage lifecycles. In the lytic cycle, the virus takes over the host machinery to produce many new virions, and the host cell eventually bursts (lyses) to release them. In the lysogenic cycle, the phage DNA integrates into the host genome as a prophage (or provirus) and remains dormant as the host divides, with no virion production until an inducing stress triggers the switch to the lytic cycle. So the statement that fits best is that the lytic cycle produces virions until the cell lyses, while the lysogenic cycle involves integration and dormancy until stress activates it. Stress can prompt the prophage to excise from the host genome and enter the lytic cycle, producing virions. This explains why the other descriptions don’t match: dormancy and integration aren’t features of the lytic cycle, virion production isn’t immediate in lysogeny, and lysogeny does not end with unavoidable cell death without dormancy.

The key idea here is understanding the two phage lifecycles. In the lytic cycle, the virus takes over the host machinery to produce many new virions, and the host cell eventually bursts (lyses) to release them. In the lysogenic cycle, the phage DNA integrates into the host genome as a prophage (or provirus) and remains dormant as the host divides, with no virion production until an inducing stress triggers the switch to the lytic cycle.

So the statement that fits best is that the lytic cycle produces virions until the cell lyses, while the lysogenic cycle involves integration and dormancy until stress activates it. Stress can prompt the prophage to excise from the host genome and enter the lytic cycle, producing virions. This explains why the other descriptions don’t match: dormancy and integration aren’t features of the lytic cycle, virion production isn’t immediate in lysogeny, and lysogeny does not end with unavoidable cell death without dormancy.