Which cycle leads to host cell lysis and phage release?

• A. Lytic
• B. Lysogenic
• C. Prophage
• D. Dormant

Answer: (A)

The cycle that leads to host cell lysis and release of phage particles is the lytic cycle. In this pathway the phage attaches to the bacterial surface, injects its DNA, and then rapidly takes over the host’s machinery to replicate the phage genome and synthesize viral proteins. These components assemble into new viral particles inside the cell, and the cell is finally destroyed by lytic enzymes that break down the cell wall, releasing a flood of new phages. In contrast, the lysogenic cycle involves integrating the phage genome into the host chromosome as a prophage and replicating with the host without killing it immediately; only under certain conditions can a prophage switch to the lytic cycle. The term prophage refers to that integrated genetic state, not the process that causes lysis, and dormancy isn’t a formal cycle describing phage behavior in this context.