UV breaks the bonds between A and T. T bases form dimers, which causes kinks in the DNA helix, and so cannot be transcribed correctly.also indirectly creates free radicals
Ultraviolet (UV) radiation is a form of electromagnetic radiation that has enough energy to break chemical bonds
Ultraviolet (UV) radiation is a form of electromagnetic radiation that has enough energy to break chemical bonds. In the case of DNA, UV radiation primarily affects the bonds between the nucleotide bases. Specifically, it can break the bonds between adenine (A) and thymine (T) bases.
When UV radiation interacts with DNA, it can cause adjacent T bases to react with each other and form what are known as thymine dimers. Thymine dimers occur when two T bases become covalently bonded to each other, leading to a distortion or kink in the DNA helix structure. These kinks can interfere with the normal functioning of DNA and its transcription, the process by which genetic information is transferred from DNA to mRNA.
During transcription, the DNA double helix is partially unwound, and one of the strands serves as a template for the synthesis of an mRNA molecule. However, the presence of thymine dimers resulting from UV damage can impede this process because the kinks created by the dimers disrupt the normal shape and structure of the DNA molecule, making it difficult for the transcription machinery to accurately read the DNA sequence and transcribe it properly into mRNA.
Furthermore, UV radiation indirectly creates free radicals. Free radicals are highly reactive molecules that can cause cellular damage by reacting with and damaging important cellular components, including DNA. UV radiation can generate reactive oxygen species (ROS) in the cells by directly exciting molecules or indirectly by causing damage to cellular components like membranes or mitochondria. These ROS can then interact with DNA, leading to oxidative damage and further disruptions in DNA structure and function.
In conclusion, UV radiation can break the bonds between A and T bases in DNA, leading to the formation of thymine dimers, which cause kinks in the DNA helix. These kinks can interfere with DNA transcription and other processes. Additionally, UV radiation indirectly generates free radicals, which can further damage DNA and disrupt cellular functions.
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