Final answer:
Ionizing radiation, such as X-rays and gamma rays, can ionize atoms, while non-ionizing radiation like UV light cannot. UV light causes thymine dimers to form in DNA, leading to mutations that can kill microorganisms, making it an effective microbial control method.
Step-by-step explanation:
Ionizing radiation includes types like gamma rays, X-rays, and high-energy ultraviolet radiation, which are energetic enough to knock electrons out of molecules. Non-ionizing radiation includes lower energy forms such as light, microwaves, and most ultraviolet (UV) light, which do not have enough energy to ionize atoms.
UV light limits microbial growth by inducing the formation of thymine dimers in DNA. These dimers disrupt the normal base pairing during DNA replication and can lead to mutations. The accumulation of these mutations can be lethal to microorganisms. Therefore, UV light is effectively used in water purification systems, surgical suites, and biological safety cabinets to control microbial growth.