What are the three types of DNA damage?
DNA Mutation and Repair. There are three types of DNA Mutations: base substitutions, deletions and insertions. Single base substitutions are called point mutations, recall the point mutation Glu —–> Val which causes sickle-cell disease. Point mutations are the most common type of mutation and there are two types.
What are the different mechanisms that bacteria can use to repair their damaged DNA?
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 are 4 DNA damaging agents?
DNA damaging agents are widely used in oncology to treat both hematological and solid cancers. Some commonly used modalities include ionizing radiation, platinum drugs (cisplatin, oxaliplatin, and carboplatin), cyclophosphamide, chlorambucil, and temozolomide.
What type of gene can repair damaged DNA and slow down the cell cycle?
Tumor suppressor genes are normal genes that slow down cell division, repair DNA mistakes, or tell cells when to die (a process known as apoptosis or programmed cell death).
What are the types of DNA damage?
DNA damage can be subdivided into two types: (1) endogenous damage caused by reactive oxygen species (ROS) that are derived from metabolic byproducts and (2) exogenous damage caused by radiation (UV, X-ray, gamma), hydrolysis, plant toxins, and viruses.
What is the most common mechanism for repairing damage to DNA?
Most damage to DNA is repaired by removal of the damaged bases followed by resynthesis of the excised region. Some lesions in DNA, however, can be repaired by direct reversal of the damage, which may be a more efficient way of dealing with specific types of DNA damage that occur frequently.
What type of DNA repair is unique to bacteria?
In bacteria, there are two general mechanisms for repair of DNA breaks: non-homologous end-joining (NHEJ) and homologous recombination. In some species of bacteria, the broken DNA ends can be joined directly in a manner analogous to the NHEJ pathway seen in eukaryotes2.
What are the three major mechanisms of DNA repair?
There are three types of repair mechanisms: direct reversal of the damage, excision repair, and postreplication repair. Direct reversal repair is specific to the damage. For example, in a process called photoreactivation, pyrimidine bases fused by UV light are separated by DNA photolyase (a light-driven enzyme).
What type of DNA mutation is commonly repaired by nucleotide excision repair?
For example, single stranded DNA breaks are repaired primarily by Base Excision Repair, bulky DNA adducts and crosslinks are repaired by Nucleotide Excision Repair, and smaller nucleotide mutations, such as alkylation are repaired by Mismatch Repair.
What is DNA repair mechanism botany?
Nucleotide excision repair is a general repair mechanism employed by both prokaryotic and eukaryotic cells to remove a variety of structurally different DNA lesions. The main substrates of NER are UV-induced photoproducts and other bulky DNA adducts that generate substantial conformational changes in DNA.
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 is nucleotide excision repair mechanism?
Nucleotide excision repair is a mechanism in which a damaged region of DNA is cut out and replaced by DNA synthesized using the undamaged strand as template.