Bacteriophage biology — The viral DNA of a temperate phage integrates into the host chromosome and becomes a prophage acting like a gene. This state is called:

Introduction:
Temperate bacteriophages can choose between two developmental pathways. Integration of phage DNA into the host chromosome establishes a stable relationship with the bacterium. Knowing the terminology is fundamental to microbial genetics.

Given Data / Assumptions:

• Temperate phage can integrate into host DNA.
• Integrated phage DNA is called a prophage.
• Question asks for the name of this integrated state.

Concept / Approach:
Lysogeny is the state in which a prophage is maintained and replicated with the host chromosome during cell division. Under certain triggers, the prophage can excise and enter the lytic cycle to produce new virions and lyse the cell.

Step-by-Step Solution:

Verification / Alternative check:
Classic lambda phage models define lysogeny as stable prophage carriage with repression of lytic functions by repressor proteins.

Why Other Options Are Wrong:

• Spontaneous induction: describes exit from lysogeny, not the integrated state.
• Lytic phase: opposite program with phage production and cell lysis.
• None of these: incorrect because lysogeny precisely matches the description.

Common Pitfalls:
Confusing the state (lysogeny) with the transition out of it (induction).

Final Answer:
Lysogeny