DNA damage can occur as a result of exposure to chemicals or ultraviolet radiati
ID: 218046 • Letter: D
Question
DNA damage can occur as a result of exposure to chemicals or ultraviolet radiation. What happens during nucleotide excision repair of damaged DNA? OEnzymes delete an incorrect DNA sequence, pull the gap closed, and join the bases on either side of the gap together Enzymes cut out the damaged gene, copy the same gene from the homologous chromosome, and insert the copy Enzymes detect an incorrect DNA base pairing in a DNA strand, remove the incorrect base, and insert the correct base. Enzymes open the DNA strand, remove a segment of DNA from the strand that contains the damage, and resynthesize the correct DNA sequence.Explanation / Answer
Enzyme open the DNA strand, remove a segment of DNA from the strand that contains the damage, and resynthesize the correct DNA sequence
Nucleotide-Excision Repair DNA lesions that cause large distortions in the helical structure of DNA generally are repaired by the nucleotide-excision system The general pathway of nucleotide-excision repair is similar in all organisms.
1. An excinuclease binds to DNA at the site of a bulky lesion and cleaves the damaged DNA strand on either side of the lesion.
2. The DNA segment—of 13 nucleotides (13 mer) or 29 nucleotides (29 mer)—is removed with the aid of a helicase.
3. The gap is filled in by DNA polymerase, and 4 the remaining nick is sealed with DNA ligase
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