Dna damage repair ppt. Understanding these DNA-REPAIR. The document discusses the importance of DNA damage repair systems to maintain genetic integrity, highlighting various agents that can cause DNA damage, such as radiation and environmental chemicals. DNA damage by UV light 7. Why do we care? Genetic diseases Cancer. Jan 13, 2025 · Explore the mechanisms of DNA damage, repair principles, and group member discussions. It details the semi-conservative nature of DNA replication, the processes involved in prokaryotic and eukaryotic systems, and the mechanisms of DNA repair, which are crucial for maintaining genetic integrity and preventing mutations DNA Damage and Repair PowerPoint PPT Presentation 1 / 42 Remove this presentation Flag as Inappropriate I Don't Like This I like this Remember as a Favorite Share 1) The document discusses various agents that can damage DNA like radiation, chemicals, and how the cell repairs this damage through mechanisms like base excision repair, nucleotide excision repair, mismatch repair, and strand break repair. 2 2,880 Oxidized DNA 10. 1) Wide functionality to create high-quality and attractive animations. is extensively damaged; many are involved in DNA repair & mutagenesis. It discusses the key components and processes involved in DNA replication, including replication origins, forks, primers, and polymerases. Defects in DNA repair The document discusses the SOS repair mechanism, a crucial system for maintaining DNA integrity in organisms by repairing damage caused by various factors like radiation and chemicals. PPT slide on PPT On DNA Damage And Repair compiled by Souradeep Chatterjee. 化学修饰 光损伤. Single stranded DNA breaks can also be repaired through this process. DNA is constantly exposed to damage from the environment and errors during replication. However, DNA is routinely damaged by oxidative stress of normal cellular processes every day. Chain breaks include single and double stranded DNA is constantly damaged by radiation, chemicals, and other agents. DNA Damage and Repair 2. DNA can be damaged by physical, chemical, and environmental agents through various types of alterations including single or double base changes, breaks in the DNA chain, or cross-linkages between bases. 复制错误. There are multiple pathways for repairing DNA damage, including direct reversal, base excision repair, nucleotide excision repair, and mismatch repair. pptx), PDF File (. . Featuring cutting-edge graphics and expert insights, this resource covers essential methods and tools for accurate analysis. Bibliography 3. Central Dogma ( 中心法则 ) DNA Replication ( 复制 ) Testing Models for DNA replication Semi-conservative replication ( 半保留复制 ) Evidence for Semi-Discontinuous ( 半不连续 ) Replication E. Visible light or liquid holding enhances survival 11. 分子生物学研究中心. Various repair mechanisms have evolved to correct DNA damage and prevent mutations. The SOS response 1) DNA mutations can occur spontaneously from errors in replication or due to environmental mutagens, and can lead to genetic disorders if unrepaired. Cells use several DNA repair systems to repair damage and maintain DNA integrity, including base excision repair, nucleotide excision repair, and repair of alkylation damage. Covering DNA structure, damage types, mutations, repair processes, factors influencing damage, and various sources like radiation, hydrolysis, alkylation, and oxidation. DNA Mutations . Explore DNA repair pathways and the significance of maintaining genomic stability against mutations. 链内交联 DNA- 蛋白质 交联 DNA 链断裂. DNA damage. P/P. DNA replication is asymmetrical. It notes that UV light induces the formation of covalent bonds between thymine and cytosine bases, creating cyclobutane pyrimidine dimers and 6,4 photoproducts. Repair of DNA damage caused by ionizing radiation (IR) is defined by the lesion to be repaired:. It details the components of the SOS system, including repressor and regulator genes, and explains the mechanisms of repair such as nucleotide excision repair and translesion DNA synthesis. It also describes common causes of mutations such as errors in DNA replication and chemical damage, along with various repair mechanisms like DNA polymerase proofreading and nucleotide excision repair. Theory and Repair Complex organisms with large genomes and long generation times contain many cells that divide very slowly or not at all. At Sunny Appliance Repair, we aim to provide our customers with a complete solution to their appliance problems. The initial step involves damage recognition by XPA, which is aided by replication protein A (RPA). The major polypeptides involved in this pathway are: i) DNA photolyases, the enzymes responsible for removing cyclobutane Sep 23, 2014 · DNA Replication , DNA Damage and Repair. DNA is constantly damaged by radiation, chemicals, and oxidation. mansoor1@bradford. It describes how these damages occur from oxidation, chemotherapy, radiation therapy, and ultraviolet light. DNA 损伤类型. Unrepaired lesions can alter gene transcription or cause mutations. txt) or view presentation slides online. DNA repair mechanisms are essential to correct damage to DNA and prevent mutations. 6075 Phone 713-792-8941 E-mail rlegersk_at_mdanderson. If damage Aug 28, 2012 · DNA damage and repair summary . Failure to repair can increase mutations. pptx - Free download as Powerpoint Presentation (. An Overview • Because each cell contains only one or two copies of its DNA, the DNA sequence is highly protected from harm. Jul 18, 2014 · DNA repair mechanisms. The cell has multiple DNA repair mechanisms to correct damage including base excision repair, nucleotide excision repair, mismatch repair, and double-strand break repair. Nature. During replication – corrected by proof reading Environmental factors : physical and chemical factors – corrected by DNA repair mechanisms. It occurs in 5'-3' direction and is semidiscontinuous on the lagging strand. Learn more: Note on DNA Repair – Introduction The preview of the PPT on ‘DNA Repair Mechanisms‘ will load here DNA repair is a collection of processes cells use to identify and correct damage to DNA molecules. excision repair single strand break (SSB) repair double-strand break (DSB) repair other repair types ( ie crosslink) This document discusses how DNA damage occurs through endogenous and exogenous sources, and the importance of DNA repair in maintaining genomic integrity and preventing cancer. SOS response genes are induced when the bacterial chr. It elaborates on the types of DNA damage, sources, causes, consequences, and various repair mechanisms, including direct repair, excision repair, mismatch repair, and recombinational repair. 缺失碱基位 It details different types of DNA damage and repair processes, including direct damage reversal, excision repair, and mismatch repair, as well as the significance of these mechanisms in preventing mutations and diseases. Mutation. Defects in repair cause disease Common types of DNA damage DNA repair pathways Direct enzymatic repair Base excision repair Nucleotide excision repair Mismatch repair Double-strand break repair Non-homologous end joining Slideshow 719090 by ziv DNA Damage Can Be Repaired 1. Sep 14, 2014 · DNA damage and repair. See Stryer p. Deficiencies in DNA repair lead to cancer. Ultimately, these processes are essential to prevent genome instability, cancer risk, and other diseases DNA can be damaged through various means, including single base alterations, double base alterations, chain breaks, and cross-linking. Direct reversal directly converts damaged nucleotides back to their Title: DNA Damage and Repair 1 DNA Damage and Repair 2 ??? It is well-known that DNA can be damaged by radiation. Outline. Chakravarty MBBS , MD. DNA damage occurs when there are changes to the structure of DNA that can disrupt its proper functioning. coli is the best-studied example. Nucleotide excision repair removes short fragments of 24-32 bases to repair more substantial damage like thymine dimers Identification and characterization of a human DNA glycosylase for repair of modified bases in oxidatively damaged DNA. e. 9 120,000 Single-strand break this is a powerpoint presentation about types of mutations and how it is being repaired by the DNA. These systems work together to repair or tolerate DNA damage, ensuring the overall survival and functionality of cells. Dark repair or light Apr 4, 2019 · DNA damage, cellular sensing/responding, and repair. Jan 7, 2025 · Learn about DNA repair mechanisms including reversal, excision, mismatch repair, recombination, and error-prone repair. However, these lesions are available for repair, which maintains DNA stability. These lesions inhibit DNA polymerase and replication. One strand of DNA is always retained during replication 1. Radiobiology 2012. Replication begins at an origin and proceeds bidirectionally. Mar 22, 2019 · The Damage and Repair of DNA Two main types of DNA damage: *point mutations *structural changes The molecular basis of point mutations 1. Jul 18, 2014 · DNA Repair 1 : Types of DNA damage. DNA can be damaged by various agents that cause changes to bases, formation of dimers, and breaks. UV survival curves 10. Base excision repair removes individual damaged bases. 氧自由基. Involved in protein synthesis that can only prevent the transduction of mutations to daughter cells by means of efficient DNA damage repair machinery. 烷化剂. Additionally, it outlines genetic Jul 19, 2014 · STEP 4Proofreadingcorrecting errors in replication Mismatch repair • DNA pol III – proofreads nucleotides against the template strand Excision repair • nuclease – cuts damaged segment • DNA pol III and ligase– fill the gap left Telomeres at 5’ ends of lagging strands • no genes, only 100 – 1000 TTAGGG sequences to protect DNA is constantly damaged by environmental and cellular factors, causing over 100,000 lesions per day. It also covers DNA recombination, its mechanisms, and models, emphasizing the importance of genetic variation The document discusses the structure, damage, and repair mechanisms of DNA, outlining its significance as the genetic material in various organisms. , recombination can be used to repair double-strand breaks. 3 Similarly, it is important to learn if radiation- damaged DNA is The document discusses DNA replication and repair, explaining that DNA is the hereditary material in living organisms and outlines its structure as a double helix. It explains how DNA damage occurs and emphasizes the importance of these repair processes in maintaining genetic stability. g when repair has not occurred prior to replication. Excision repair is a multi-step process where the damaged section of DNA is cut out and replaced with new DNA Sep 21, 2014 · 第六章 DNA 损伤与修复 DNA damage and repair. 碱基脱落 碱基修饰 & 去氨基化. Error-prone repair Many cells have mechanisms that enable them to synthesize DNA repair enzymes as an emergency response to severe DNA damage. It details various agents that cause DNA damage, including radiation and environmental chemicals, and describes different types of DNA damage and repair systems such as direct damage reversal, base excision repair, and nucleotide excision repair. ac. These pathways remove damaged DNA sections and replace them with the correct DNA repair mechanisms are essential for maintaining genomic integrity. The Jan 9, 2025 · 1. The next section will highlight common types of DNA damage and their effects. DNA repair systems are defenses that to protect genome integrity. Mar 21, 2019 · Cellular Response to DNA Damage - Repair. • DNA can also be altered by mistakes made during its own replication or recombination. pdf), Text File (. Recombination repair: retrieval of information from a homologous chromosome 5. Excision repair removes damaged sections of DNA through base excision repair which removes single damaged bases using glycosylases and AP endonucleases, or nucleotide excision repair DNA can be damaged through exposure to UV light, mechanical shearing, and other means. Base excision repair involves removal of damaged bases by glycosylases and AP endonucleases followed by filling in of the gap DNA Repair Mechanism PPT | What is DNA Repair? DNA Damaging Agents, DNA ‘lesions’, Different DNA Repair Mechanisms in the Cell, Noble Prize in Chemistry- 2015, Pyrimidine Dimer Formation, Spontaneous Depurination, Spontaneous Deamination of Bases, Errors in DNA Replication. DNA repair mechanisms are discussed, including This document provides lecture notes on DNA replication, damage, and repair. Already proof reading !! Why Repair ?. There are several mechanisms of repair, including photoreactivation, excision repair, recombination repair, SOS repair, and mismatch repair. DNA can be damaged through various mechanisms including base substitutions during replication, base changes due to instability, and damage from chemicals and environmental agents. " The mechanism Strand separation, followed by copying of each strand. The document discusses DNA mutations, defined as permanent changes in the nucleotide sequence of DNA, and outlines three types: base substitutions, deletions, and insertions. Most oxidized bases are removed from DNA by enzymes operating within the Base Excision Repair (BER) pathway. Ridpath Rosenau 347 966-6141. These repair pathways help maintain the integrity of The document discusses various types of DNA damage including deamination, depurination, UV light-induced T-T and T-C dimers, alkylation, oxidative damage, replication errors, and double-strand breaks. Cellular Responses to DNA Damage. There are several types of DNA damage including mismatches, modified DNA bases, and single or double strand breaks. ENVR 430: Health Effects of Environmental Agents October 3, 2008 John R. Single base alterations include depurination, deamination, alkylation, base analogue incorporation, and mismatch bases. S. • Damage and sequence DNA Replication and Repair. Some proteins involved in repair also function in recombination. Molecular Mechanisms of DNA Damage and Repair discusses the various types of DNA damage including base damage, mismatches, pyrimidine dimers, intercalation, crosslinking, and single and double strand breaks. Base substitution (mismatches) transition transversion 2. 2) It also discusses several diseases associated with defective DNA repair systems like Xeroderma pigmentosum, Ataxia telangiectasia, Bloom syndrome The document discusses DNA repair, emphasizing its critical role in maintaining genetic stability. High-fidelity replication depends on polymerase DNA repair Direct repair Excision Depyrimidation 1. However, cells have evolved mechanisms for repairing DNA damaged by chemicals or radiation. The main repair pathways are direct reversal, excision repair including nucleotide excision repair and base excision repair, and mismatch repair which fixes errors made during replication. The page provides an extensive overview of DNA mutations and repair mechanisms, aimed at biochemistry majors. Genome maintenance mechanisms for preventing cancer. ppt / . DNA Background. Try it for your science presentations! This document discusses how DNA damage occurs through endogenous and exogenous sources, and the importance of DNA repair in maintaining genomic integrity and preventing cancer. Replication occurs through Dec 13, 2018 · The key DNA repair mechanisms discussed are direct reversal, base excision repair, nucleotide excision repair, mismatch repair, and double-strand break repair. Rebecca Fry, Ph. If a DNA polymerase encounters a damaged DNA base in the template DNA during replication it may place a random nucleotide base across from the lesion. There are several types of DNA damage, including modified bases, mismatches, and breaks in the DNA backbone. DNA damage & repair Maqsood Mansoor m. uk 2. Oct 9, 2014 · Section F - DNA Damage, repair and recombination. DNA 重组. Proc Natl Acad Sci USA 99: 3523-3528 Hoeijmakers JHJ (2001). All 3 genomes in plants constantly being damaged by UV and other forms of radiation, chemicals, and other stresses (e. Cells use direct reversal, excision repair, and mismatch repair to 1) DNA can be damaged through radiation, free radicals, and chemicals. DNA encodes all genetic information Original assumption: blue-print for life must be fundamentally stable Edit our DNA Repair Process PowerPoint Scene to present the components involved in correcting molecular errors. 第一节 DNA 损伤的原因及后果. Base excision repair The document summarizes DNA replication, repair, and recombination. Reversal of DNA Damage Enzymatic photoreactivation Ligation of DNA strands Repair of photoproduct Tolerance of DNA Damage DNA damage can occur endogenously from normal cellular processes or exogenously from external agents like UV rays. It covers types and causes of DNA mutations, mechanisms of DNA damage, and major DNA … DNA Repair & Recombination All 3 genomes in plants constantly being damaged by UV and other forms of radiation, chemicals, and other stresses (e. Excision repair includes base excision repair, nucleotide excision repair, mismatch repair, and strand break repair. The document discusses DNA repair and recombination mechanisms, outlining the types of DNA repair systems including direct, base excision, nucleotide excision, and mismatch repair, as well as the significance of these processes in maintaining genetic integrity and preventing diseases. DNA Damage . Substitution mutations : one base pair for another, e. , oxidative, heat). Evidence for repair of UV damaged DNA 8. Title: DNA Replication and Repair 1 DNA Replication and Repair 2 Watson and Crick Predicted Semi-conservative Replication of DNA Watson and Crick "It has not escaped our notice that the specific (base) pairing we have postulated immediately suggests a possible copying mechanism for the genetic material. 8-oxoG. This damage can include breaks in DNA strands, missing or altered bases, and cross-linking between DNA and other molecules. • In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many as 1 million individual molecular lesions per day. DNA-Damage-and-Repair-Mechanisms. Error-prone repair Last resort for DNA repair, e. DNA repair-r. Explore how enzymes undo DNA damage and the role of photoreactivation, excision repair, and mismatch repair in maintaining genomic integrity. 3) The study found that DNA damage increased phosphorylation and The document discusses DNA repair mechanisms, detailing various types including base excision repair (BER), nucleotide excision repair (NER), mismatch repair, homologous recombination repair (HRR), and non-homologous end joining (NHEJ). Inheritable change in genetic material Cells from cell division; offspring from reproduction Somatic mutations Mitosis yields genetically identical cells can lead to mosaicism Tumor – uncontrolled growth Germ-line mutations DNA repair is essential to correct damage to DNA that occurs during replication or from environmental factors like radiation and chemicals. Damage to DNA may lead to change of the genetic information (mutation) affect gene expression DNA repair is a collection of processes cells use to identify and correct damage to DNA. Base excision repair fixes small base damages through removal and replacement. whether it is a leaking 4. The document emphasizes that without proper DNA repair, damage can lead to genomic instability and disease. DNA damage and repair How is DNA damaged? How is DNA repaired? How does the type of damage impact repair? Accumulated DNA damage=death (by cancer, or old age) Sep 16, 2012 · DNA Damage and Repair. Direct repair converts damaged nucleotides directly back to their original structure using enzymes like photolyase. Additionally, it notes that defective DNA repair systems are linked to several genetic disorders and cancers. To prevent disease, cells have multiple repair pathways including base excision repair, nucleotide excision repair, mismatch repair, and double-strand break repair. Repairing: DNA repair mechanisms of proteins and enzymes (such as DNA Polymerase I and II) may locate distortions in the strands between replication events and remove a piece of the strand, DNA polymerases will fill the gap, and DNA ligase will seal the strand Aug 7, 2012 · DNA damage and repair. DNA repair is a cellular mechanism that corrects damage to DNA before it causes mutations or chromosomal abnormalities. Failure to repair DNA damage can lead to mutations. The combined action of DNA helicase II, SSB, and one of many different exonucleases (only two are labeled) removes a segment of the new strand between the MutH cleavage site and a point just beyond the mismatch. Key enzymes and proteins involved DNA is constantly exposed to damage from external and internal sources. It discusses the process of DNA replication including the three main steps of initiation, elongation, and termination. There are several pathways for repairing different types of DNA damage: mismatch repair fixes errors during DNA replication, base excision repair removes damaged bases, nucleotide excision repair replaces larger sections of damaged DNA, and double-strand break repair fixes breaks in both DNA strands. g. ppt - Free download as Powerpoint Presentation (. The Explore key targets of cancer research and cell signaling research with the DNA damage response (DDR) pathway and do a deep dive into ATM, ATR, and p53 mechanisms involved in DNA damage checkpoints. It describes various types of DNA damage including base modifications, single-strand breaks, and double-strand breaks that can be caused by reactive oxygen species, radiation, chemicals and replication errors. Dr. Failure to repair damaged DNA leads to mutations, which are permanent changes in the DNA sequence. The main types of DNA repair are direct reversal, base excision repair, nucleotide excision repair Sep 8, 2023 · DNA Damage and DNA Repair To overcome the harmful effects of DNA damage, cells have various systems such as DNA repair mechanisms, damage tolerance pathways, cell cycle checkpoints, and cell death pathways. Double base alterations include pyrimidine dimers and purine dimers caused by UV radiation. 768-773. It details types of DNA damage, such as single base changes and structural changes, and illustrates their causes and effects. 3. UV survival curves 9. 2 24,000 Depurination 35. • DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. Finally, it briefly touches on mobile genetic elements and retrotransposons that can Nov 2, 2014 · Chapter 18 – Gene Mutations and DNA Repair. s. • DNA is a relatively stable molecule, but Earth’s natural environment is quite toxic, and damage to DNA is inevitable. Explore how mutations like 8-oxoguanine impact DNA replication and the role of enzymes like OGG1 in repairing damaged bases. 411: 366-374 Krokan HE, Nilsen H, Skorpen F, Otterlei M and Slupphaug G (2000). coli DNA polymerases Details of DNA Radiation damage to DNA A: Two-dimensional representation of the normal DNA helix B: A break in one strand is of little significance because it is repaired using the opposite strand as a template C: Breaks in both strands, if separated, are repaired as independent breaks D: If breaks occur in both strands and are directly opposite or separated by only a few base pairs, this may lead to a Jan 5, 2025 · Most carcinogens damage DNA. Point mutations are the changes of a single base pair. 2) The cell has multiple DNA repair mechanisms to recognize and fix damage, such as base excision repair and nucleotide excision repair. Apr 5, 2019 · DNA Damage, Mutations, and Repair . - Download as a PPT, PDF or view online for free DNA damage and repair PowerPoint PPT Presentation 1 / 17 Remove this presentation Flag as Inappropriate I Don't Like This I like this Remember as a Favorite Share DNA polymerase is responsible for copying and repairing DNA. UV irradiation 5. It then summarizes different DNA repair pathways such as base excision repair, nucleotide excision repair, mismatch repair, direct repair, recombination repair, and non-homologous end-joining Feb 26, 2025 · Learn the importance of studying DNA damage, its impact on genetic information, repair mechanisms, and implications on health. Measurement techniques for different types of DNA damage are also covered. The document then describes 4. 可见光. Each separated strand Apr 8, 2025 · DNA chains are only relatively stable, as a result of which DNA damage can occur mainly in the form of thymine dimers. T for G • the most common form of mutation • transitions; purine to purine and pyrimidine to pyrimidine. Jan 5, 2025 · Description Unlock the secrets of DNA damage detection with our comprehensive PowerPoint presentation deck. Cells use multiple repair pathways like direct reversal, base excision repair, nucleotide Title: Lecture: DNA Repair Mechanisms 1 Lecture DNA Repair Mechanisms By Randy Legerski, Ph. Cells have developed multiple pathways to repair DNA damage and prevent mutations, including base excision repair, nucleotide excision repair, and mismatch repair. The 3′ incision is catalyzed by XPG, and the 5′ incision is brought about by a complex containing XPF and ERCC1. Scientists are trying to determine whether DNA damage from radiation is the same or different from normal damage. ppt), PDF File (. • Many of these lesions cause structural damage to the Additionally, it covers various DNA repair mechanisms to correct replication errors and damage from environmental factors. D. org 2 Common Types of DNA Damage and Spontaneous Alterations Exogneous Sources UV (sunlight) Pollution (hydrocarbons) Radiotherapy Ionizing Radiation X-rays Chemotherapy (Alkylating agents) Cisplatin Mitomycin C Cyclophosphamide Psoralen DNA repair mechanisms in prokaryotes involve direct repair, excision repair, and mismatch repair. It is semiconservative, meaning the parental double helix separates and each strand acts as a template for a new partner strand. How does the polymerase copy across a non-pairing, mutated base, or an apyrimidinic/apurinic site? DNA polymerase III usually dissociates at a nick or a lesion. During repair of DNA damages DNA Repair Various checkpoints in the body. Defects in human DNA repair pathways can cause inherited diseases like xeroderma pigmentosum and progeria, characterized by premature aging DNA mutations can also result through the replication of DNA that has been damaged by endogenous or exogenous agents. Mutation occurs when the DNA structure of a gene is changed, such as through Dec 11, 2024 · Learn about the molecular mechanisms of oxidative DNA damage caused by various factors such as metabolism and toxins, and the repair pathways involved in maintaining genomic integrity. . Perfect for researchers and professionals, elevate your understanding of DNA damage assessment today. F1 Mutagenesis Mutation , Replication fidelity , Physical mutagens , Chemical mutagens , Direct mutagenesis , Indirect mutagenesis F2 DNA damage DNA lesions , Oxidative damage , Alkylation , Bulky adducts F3 DNA repair Slideshow Nucleotide excision–repair in mammalian cells. Aug 25, 2012 · Presentation Transcript 1. These include direct reversal, base excision repair, nucleotide excision repair, mismatch repair, and recombinational repair. 1. Five primary DNA repair pathways nucleotide excision repair, base excision repair, mismatch repair nonhomologous end joining, homologous recombinational repair. 2. The most common types of DNA damage include deamination, depurination, pyrimidine dimers caused by UV light, alkylation by chemicals, and oxidative damage. Apr 11, 2017 · DNA damage & repair: Transcript DNA damage and repair and their role in carcinogenesis A DNA sequence can be changed by copying errors introduced by DNA polymerase during replication and by environmental agents such as chemical mutagens or radiation. 3) The types of DNA damage radiation can cause including single and double strand breaks, DNA-DNA and DNA-protein crosslinks, and chromosomal aberrations. SOS reponse ("Save Our Ship") in E. Repair A) Direct Damage Reversal The direct reversal of DNA damage is by far the simplest repair mechanism that involves a single polypeptide chain, with enzymatic properties which binds to the damage and restores the DNA genome to its normal state in a single-reaction step. 核苷类似物. Office Y5. We have prepared a DNA Damage Repair PowerPoint template for creating a presentation. It also examines DNA repair mechanisms for errors, damage like depurination, and double-stranded breaks. Proofreading by DNA polymerases - They correct miscopied bases during replication. Molecular and Cell Biology This document discusses DNA damage caused by ultraviolet light in the form of pyrimidine dimers, as well as the DNA repair process of photoreactivation. 6 84,000 N7-MethylGuanine 50. U. m C. The XPB and XPD helicases (part of the TFIIH complex) unwind the DNA to facilitate incision on either side of the lesion. Title: DNA damage and repair summary 1 (No Transcript) 2 DNA damage and repair summary Defects in repair cause disease Common types of DNA damage DNA repair pathways Direct enzymatic repair Base excision repair Nucleotide excision repair Mismatch repair Double-strand break repair Non-homologous end joining Homologous recombination 3 DNA repair defects cause disease 4 Common types of DNA damage Most DNA damage is repaired by two general classes of mechanisms: direct reversal of the chemical reaction that caused the damage, or removal and replacement of damaged bases. There are two main types of DNA repair - direct reversal and excision repair. They can result (i) from replication errors,(ii) from damage to the DNA, or (iii) from errors during repair of damage. Photoreactivation repair 13. DNA replication is a semi-conservative process where the parental DNA strands separate and new complementary strands are built to form two new DNA molecules, each with one original and one new strand. Cells have several DNA damage repair mechanisms to fix alterations to maintain genome integrity. Specific repair pathways have evolved to fix different types of Dna damage and repair - Download as a PDF or view online for free Damaged DNA must be repaired to prevent mutations from being passed down to future generations. DNA damage, due to environmental factors and normal metabolic processes inside the cell, occurs at a rate of 1,000 to 1,000,000 molecular lesions per cell per day. 电离辐射. Learning objectives. Different ways of DNA Damage BilalNaveed Factors mainly responsible for DNA Damage The document discusses DNA damage, its repair mechanisms, and the clinical significance of deficient DNA repair. Contents. • Types of damage •Direct reversal of damage •Excision repair in prokaryotes and eukaryotes base excision nucleotide excision •Nonhomologous end-joining in eukaryotes •Mismatch repair •Recombination repair, error-prone bypass and error-free bypass. Around 1 million lesions can occur per cell per day due to normal metabolic activities and environmental factors like UV light. H +. This document describes different types of DNA damage including mismatches, missing or altered bases, single and double strand breaks, and cross-linking. 2) There are several types of DNA damage, including single or double base alterations, chain breaks, and cross-linking. DNA Damage. DNA: the genetic material ensuring preservation of the genetic information its transfer to progeny its transcription and translation into proteins. 2) High-quality images and inscriptions DNA replication is the process by which DNA copies itself for cell division. Living organisms have multiple DNA repair mechanisms, including photoreactivation, base excision repair, nucleotide excision repair, and mismatch repair. 7kv4 kak ga u4a z8zi9qo 9x83u cdb5w cotgtf nx uueo2