Final answer:
Gamma radiation is used to sterilize plastic Petri plates by damaging the DNA of microorganisms present. It is an effective method, particularly for heat-sensitive materials.
Step-by-step explanation:
Gamma radiation is commonly used to sterilize plastic Petri plates in laboratories. It is a form of ionizing radiation that can easily penetrate materials like plastic. The process involves exposing the Petri plates to gamma rays, which damages the DNA of any microorganisms present, effectively sterilizing the plates. Gamma irradiation is a reliable and efficient method for sterilization, especially for heat-sensitive materials that cannot be autoclaved.