In a bacteriophage lytic infection, the infection cycle concludes with which event?

• A. Establishment of a chronic infection with continuous budding and no host cell death
• B. Formation of endospores to protect the phage genome during dormancy
• C. Lysis of the host cell and release of newly assembled virions
• D. Integration of the phage genome into the host chromosome as a prophage

Answer: (C)

Verified step by step guidance

1. Understand the nature of a lytic infection cycle in bacteriophages: it is a process where the phage infects a bacterial cell, replicates its genome, assembles new virions, and then causes the host cell to burst.
2. Recall that in the lytic cycle, the phage does not integrate its genome into the host chromosome (which is characteristic of the lysogenic cycle), nor does it establish a chronic infection with continuous budding.
3. Recognize that formation of endospores is a bacterial survival mechanism and is not related to bacteriophage infection cycles.
4. Identify that the final step of the lytic cycle is the lysis (breaking open) of the host bacterial cell, which releases the newly assembled phage particles to infect other cells.
5. Conclude that the event marking the end of the lytic infection cycle is the lysis of the host cell and release of new virions.