In lysogenic infection, the integrated viral DNA is called a prophage.

• A. Prophage
• B. Plasmid
• C. Episome
• D. Genome

Answer: (A)

During lysogenic infection, a temperate phage inserts its DNA into the bacterial chromosome and remains there as a dormant, integrated element. This integrated viral genome is called a prophage. It’s copied along with the host DNA and passed to every new cell during division, which is why the phage genome persists without destroying the host. The prophage can later be induced to excise and enter the lytic cycle to produce new virions.

A plasmid is separate, circular DNA that exists outside or alongside the chromosome, not integrated into it. The genome refers to the entire genetic content of the organism, not specifically to an integrated viral sequence. An episome is a genetic element that can exist either integrated into the chromosome or as a plasmid, but when the phage DNA is integrated into the host chromosome, the precise term is prophage.