Final answer:
Radiation in the forms of ionizing radiation and UV light can kill bacterial cells or inhibit their growth. Ionizing radiation damages the cell's components, including DNA, while UV light forms thymine dimers in the DNA that cause mutations and kill microorganisms.
Step-by-step explanation:
Radiation in various forms, such as ionizing radiation and ultraviolet (UV) light, can kill bacterial cells or inhibit their growth. Ionizing radiation, such as X-rays and gamma rays, can penetrate into the cell and damage its components, including the DNA. This damage can lead to mutations and eventually cell death. UV light, on the other hand, forms thymine dimers in the DNA, which can cause mutations that kill microorganisms.