In the lytic cycle, what event leads to release of new virions?

• A. Viral DNA integrates into host chromosome
• B. Host cell burst and release of viruses
• C. Attaches to host cell and inserts genetic material
• D. Environmental trigger starts lysogenic cycle

Answer: (B)

During the lytic cycle, new virions are released when the host cell undergoes lysis, bursting open after viral replication and assembly inside. Phage-encoded enzymes, such as holins and endolysins, break down the cell wall and membrane, releasing the assembled viruses to infect other cells. The other scenarios describe different stages: integrating viral DNA into the host genome is a lysogenic-cycle event; attaching to the host and injecting genetic material is the entry step; an environmental trigger starting the lysogenic cycle refers to induction or transition to lysogeny, not the release in the lytic cycle.