What are the types of DNA repair?
At least five major DNA repair pathways—base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), homologous recombination (HR) and non-homologous end joining (NHEJ)—are active throughout different stages of the cell cycle, allowing the cells to repair the DNA damage.
What is the most common method for repairing nucleotide errors in DNA?
Most of the mistakes during DNA replication are promptly corrected by DNA polymerase by proofreading the base that has been just added ([link]). In proofreading, the DNA pol reads the newly added base before adding the next one, so a correction can be made.
What is the most common DNA damage?
While exogenous sources of genotoxic stress can be quite potent, endogenous threats are constant and relentless (Table 1). The most common DNA lesion is hydrolytic cleavage of the glycosidic bond between the DNA base and sugar phosphate group, leading to abasic sites.
What are the two types of DNA repair quizlet?
What are the four types? main type of DNA repair, Nucleotide Excision, Base-Excision, Transcription Coupled Repair, Mismatch Repair.
Which is the simplest DNA repair system?
The simplest and most accurate repair mechanism is the direct reversal of damage in a single-step reaction. Direct reversal, however, applies to only a very limited number of DNA lesions.
What is DNA repair system?
DNA repair, any of several mechanisms by which a cell maintains the integrity of its genetic code. DNA repair ensures the survival of a species by enabling parental DNA to be inherited as faithfully as possible by offspring. It also preserves the health of an individual.
What is excision repair of DNA?
Excision-repair pathways involve the removal or “excision” of a stretch of DNA containing damaged DNA and the resulting gap is filled in by DNA replication using the undamaged DNA as a template. In the 1960s, several groups discovered key aspects of the NER pathway in bacteria and in mammalian cells.
What type of DNA mutation is commonly repaired by nucleotide excision repair quizlet?
Nucleotide excision repair is used to repair deletions, insertions, and helix-distorting lesions, such as thymine dimers. To learn more about this, please visit Lesson 1: DNA and RNA; Chapter – Inheritance of Genes; Subchapter – DNA Damage and Repair; Section – Excision Repair Corrects The Most Frequent DNA Lesions.
What type of damage is most likely to be corrected by nucleotide excision repair?
Nucleotide excision repair (NER) is a particularly important excision mechanism that removes DNA damage induced by ultraviolet light (UV). UV DNA damage results in bulky DNA adducts – these adducts are mostly thymine dimers and 6,4-photoproducts.
What are the DNA repair enzymes?
DNA repair enzymes are enzymes that recognize and correct physical damage in DNA, caused by exposure to radiation, UV light or reactive oxygen species. The correction of DNA damage alleviates loss of genetic information, generation of double-strand breaks, and DNA crosslinkages.