UV light

Definition

UV light is a form of electromagnetic radiation with wavelengths shorter than visible light but longer than X-rays. It is commonly used in microbiology to control microbial growth by damaging the DNA of microorganisms.

5 Must Know Facts For Your Next Test

1. UV light is most effective at a wavelength of 260-280 nm, where it causes the formation of thymine dimers in DNA.
2. Exposure to UV light can lead to lethal mutations in microorganisms, preventing their replication and survival.
3. UV light does not penetrate surfaces well, so it is mainly effective for disinfecting air, water, and surface areas.
4. Prolonged exposure to UV light can be harmful to human skin and eyes, necessitating protective measures during its use.
5. UV-C is the most germicidal range of UV light and is often used in laboratory and clinical settings for sterilization purposes.

Review Questions

• What wavelength range is most effective for UV light's germicidal action?
• How does UV light affect the DNA of microorganisms?
• Why is UV light primarily used for disinfecting surfaces rather than deeper layers or objects?

Related terms

Sterilization:

The process of eliminating all forms of microbial life, including spores.

Thymine Dimers:

Molecular lesions formed by covalent bonding between two adjacent thymine bases in DNA due to UV exposure.

Disinfection:

A process that eliminates many or all pathogenic microorganisms on inanimate objects, excluding bacterial spores.