What are the 3 steps of nucleotide excision repair?
The basic mechanism of excision repair involves: (1) damage recognition; (2) subunit assembly; (3) dual incisions that result in excision of the damage-containing oligomer; (4) resynthesis to fill in the gap; and (5) ligation to regenerate an intact molecule.
What is the correct order of events during excision repair?
What is the correct order for the following events in excision repair of DNA? (1) DNA polymerase I adds correct nucleotides by 5′-to-3′ replication; (2) damaged nucleotides are recognized; (3) DNA ligase seals the new strand to existing DNA; (4) part of a single strand is excised.
What are the two major DNA repair mechanisms?
There are two main mechanisms for repairing double strand breaks: homologous recombination and classical nonhomologous end joining. Homologous recombination involves the exchange of nucleotide sequences to repair damaged bases on both strands of DNA through the utilization of a sister chromatid.
What is nucleotide excision repair pathway?
Nucleotide excision repair (NER) is the main pathway used by mammals to remove bulky DNA lesions such as those formed by UV light, environmental mutagens, and some cancer chemotherapeutic adducts from DNA. Deficiencies in NER are associated with the extremely skin cancer-prone inherited disorder xeroderma pigmentosum.
Is DNA polymerase involved in nucleotide excision repair?
Nucleotide excision-repair uses DNA polymerases delta or epsilon to resynthesize the bases removed during repair of pyrimidine dimers and other bulky adducts in DNA. Similarly, mismatch-repair of replication errors appears to involve DNA polymerases delta or epsilon.
Which is the correct order in which enzymes work in excision repair?
Answer: The order of enzymes for nucleotide excision repair is D) nuclease, DNA polymerase, DNA ligase.
What is the correct enzyme order involved in nucleotide excision repair quizlet?
10. What is the proper order of the steps involved in excision repair? Recognize the damage, remove the damage, resynthesize the sequence, ligate the DNA backbone.
Which of the DNA repair pathways occurs before DNA replication?
NHEJ is especially important before the cell has replicated its DNA, since there is no template available for repair by homologous recombination. There are “backup” NHEJ pathways in higher eukaryotes.
What is the difference between nucleotide excision repair and base excision repair?
The key difference between base excision repair and nucleotide excision repair is that base excision repair is a simple repair system that works in the cells to repair single nucleotide damages caused endogenously while nucleotide excision repair is a complex repair system that works in the cells to repair …
What can cytosine deamination into?
uracil
Spontaneous deamination converts cytosine to uracil, which is excised from DNA by the enzyme uracil-DNA glycosylase, leading to error-free repair.