Lethal Effects of Uv Light

1313 Words6 Pages
The Lethal Effects of UV Light Abstract: Ultraviolet light eliminates dangerous bacteria through its fatal obstruction of bacterial DNA replication. In this experiment, three bacterium were exposed to UV light over various lengths of time to study their sensitivity to UV radiation. Ultraviolet light has lethal effects that are dependent upon the time of exposure on bacterium and rates were observed. The study showed the more time exposed to UV light, the increase in lethal death. Introduction: All of us who enjoy a brisk walk in the park or a gorgeous sunrise can appreciate the benefits of ultraviolet light from the sun: vitamin D for the skeletal and nervous systems, alleviation of depression and improve metabolism. However, UV light has even more important functions to humans: it kills pathogenic bacteria by triggering the formation of thymine dimers in the DNA of bacterial cells, destroying cellular DNA replication. UV light can have both lethal and sub lethal effects, depending on the applied emission, wavelength and intensity. UV light is nonionizing short wave-length radiation that falls between 4 nm and 400 nm in the visible spectrum (Brown, 2012). Most bacteria are killed by the effects of UV light and it is routinely used to sterilize surfaces, such as work areas of transfer hoods used for the inoculation of cultures. The primary lethal effects of UV are due to its mutagenic properties. When DNA absorbs UV light; it causes the formation of pyrimidine dimers. These form when a covalent bond forms between two adjacent thymine or cytosine molecules in a strand of DNA (Brown, 2012). These dimers deform the DNA molecule, so that DNA polymerase is unable to replicate the strand of DNA past the site of dimer formation and genes can no longer be transcribed. Because we live in a world full of external factors that can harm our cellular DNA, causing

More about Lethal Effects of Uv Light

Open Document