<span>A photon of UV light causes mutations in the double-stranded DNA via a photochemical reaction. The product of such photochemical reaction in DNA is a cyclobutane pyrimidine dimer. Dimers may be repaired by mechanisms of photoreactivation or nucleotide excision repair (NER), but if the repair doesn’t occur dimers are mutagenic.
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UV light is absorbed by a double bond in pyrimidine bases (thymine and cytosine in DNA). The bond is opened and UV-modified base can now react with neighbouring molecules. If neighbouring molecule is another pyrimidine base, the UV-modified base forms direct covalent bonds with it. A cyclic ring (cyclobutane), not normally found in DNA, is formed (links the two pyrimidines). Next step is forming a single bond between two carbon atoms on the rings.The product of this reaction is a 6-4 molecule pyrimidine-pyrimidone which is more mutagenic than cyclobutane pyrimidine dimers.</span>
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The Wernicke’s area of the brain is responsible for comprehension of language. Wernicke’s aphasia is characterized by problem comprehending spoken language or sentences. In this case, Kichi may respond with grammatically correct sentences but may pepper it with lot of words (sometimes non-existent words) that does not make sense. Kichi may not realize that they are using the wrong words. Because of problems comprehending language, Kichi may face difficulties in reading and writing. Intellectual and cognitive abilities still remain intact.
Hey there,
Answer:
<em />1) To stop beach sand erosion
2) To protect coastal property from erosion
Hope this helps :D
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