Question

In recombinant DNA technology after the bacteriophage infects a bacterial cell, plaques are formed by the _________

• A. new colonies of bacterial cells
• B. infecting bacteriophages
• C. lysed bacterial cells
• D. virions

Hint:

Each plaque usually originates from a single infecting bacteriophage.

Answer 1

The Correct Option is C

Step 1: Understanding plaques.
Plaques are clear zones formed on a bacterial lawn when bacteriophages infect and destroy bacterial cells.

Step 2: Mechanism of plaque formation.
After infection, bacteriophages multiply inside bacterial cells and cause lysis of the host cell. Repeated cycles of infection and lysis produce clear patches called plaques.

Step 3: Option analysis.
New bacterial colonies form opaque regions, not plaques.
Bacteriophages initiate infection but plaques represent dead cells.
Virions alone do not form visible plaques.

Step 4: Conclusion.
Hence, plaques are formed due to lysed bacterial cells.