DNA repair mechanisms identify and correct damage to DNA that occurs due to normal cellular processes and environmental factors. There are two main types of DNA damage: endogenous damage caused by normal cellular processes and exogenous damage caused by external agents like UV radiation and chemicals. The main repair mechanisms are base excision repair, nucleotide excision repair, direct repair via photolyases, and error-prone repair systems like SOS repair. Together, these pathways maintain genome integrity by repairing different types of DNA lesions.
DNA repair mechanisms are essential for maintaining genomic integrity. 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. Defects in DNA repair genes can lead to increased cancer risks and genetic disorders like xeroderma pigmentosum and Fanconi anemia. Overall, DNA repair helps prevent mutations from being passed to new cells.
Regulation of lac operon positive nd negativekeshav pai
The document summarizes the regulation of the lac operon in E. coli. It describes how the lac operon can be regulated both positively and negatively in response to the presence of lactose or glucose. In negative regulation, the lac repressor binds to the operator site in the absence of lactose, preventing transcription. In the presence of lactose, it binds to allolactose and dissociates from DNA, allowing transcription. Positive regulation involves cAMP and the catabolite activator protein activating transcription in the absence of glucose.
Mismatch Repair Mechanism Is One Of The Important DNA Repair Mechanism Which Recognizes And Replaces The Wrong Nucleotides. DNA Repair Is Important Since Its Failure Leads To Deadly Diseases Like Cancer. In This Presentation, You Will Learn About DNA Repair, Mismatch Repair, Proteins Involved In Prokaryotic And Eukaryotic MMR, Diagrams, Biological Importance Of MMR And References For Further Study.
This document describes the process of DNA replication in eukaryotes. It occurs in S phase of the cell cycle and involves three main stages: initiation, formation of the initiation complex, and elongation. Initiation requires the assembly of pre-replication complexes containing ORC, Cdc6, Cdt1 and MCM proteins. In S phase, Cdc45 and GINS are recruited to form the initiation complex. Elongation proceeds bidirectionally from replication forks, with leading strand synthesis continuous and lagging strand discontinuous via Okazaki fragments. Replication terminates at telomeres.
Gene silencing, also known as post-transcriptional gene silencing (PTGS), occurs when a gene is switched off by mechanisms other than mutation. It was first observed when an attempt to overexpress a pigment gene in petunia resulted in loss of pigment. This was due to co-suppression of both the endogenous gene and transgene. PTGS can occur via transcriptional gene silencing (TGS) or post-transcriptional gene silencing (PTGS) where mRNA is degraded. PTGS involves double-stranded RNA triggering cleavage and degradation of homologous mRNA through the RNA interference (RNAi) pathway, which involves dicer, siRNAs, and RISC complex.
Post-transcriptional modifications are important processes that convert primary transcript RNA into mature RNA. These modifications include 5' capping, 3' polyadenylation, and splicing of introns in eukaryotes. The modifications help make RNA molecules recognizable for translation and increase protein synthesis efficiency by removing non-coding regions. Different types of RNA undergo specific processing pathways involving nucleases, snoRNAs and other protein complexes.
DNA is constantly damaged by cellular metabolism, environmental factors like UV light, and replication errors. To prevent mutations, cells have direct damage reversal and excision repair mechanisms. Direct reversal uses enzymes like photolyases and alkyltransferases to directly restore damaged bases. Excision repair involves removing the damaged segment via pathways like base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR). BER repairs single base changes while NER excises oligonucleotides up to 30 bases. MMR corrects errors made during replication. Defects in these pathways are associated with cancers and genetic disorders like xeroderma pigmentosum.
DNA repair mechanisms identify and correct damage to DNA that occurs due to normal cellular processes and environmental factors. There are two main types of DNA damage: endogenous damage caused by normal cellular processes and exogenous damage caused by external agents like UV radiation and chemicals. The main repair mechanisms are base excision repair, nucleotide excision repair, direct repair via photolyases, and error-prone repair systems like SOS repair. Together, these pathways maintain genome integrity by repairing different types of DNA lesions.
DNA repair mechanisms are essential for maintaining genomic integrity. 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. Defects in DNA repair genes can lead to increased cancer risks and genetic disorders like xeroderma pigmentosum and Fanconi anemia. Overall, DNA repair helps prevent mutations from being passed to new cells.
Regulation of lac operon positive nd negativekeshav pai
The document summarizes the regulation of the lac operon in E. coli. It describes how the lac operon can be regulated both positively and negatively in response to the presence of lactose or glucose. In negative regulation, the lac repressor binds to the operator site in the absence of lactose, preventing transcription. In the presence of lactose, it binds to allolactose and dissociates from DNA, allowing transcription. Positive regulation involves cAMP and the catabolite activator protein activating transcription in the absence of glucose.
Mismatch Repair Mechanism Is One Of The Important DNA Repair Mechanism Which Recognizes And Replaces The Wrong Nucleotides. DNA Repair Is Important Since Its Failure Leads To Deadly Diseases Like Cancer. In This Presentation, You Will Learn About DNA Repair, Mismatch Repair, Proteins Involved In Prokaryotic And Eukaryotic MMR, Diagrams, Biological Importance Of MMR And References For Further Study.
This document describes the process of DNA replication in eukaryotes. It occurs in S phase of the cell cycle and involves three main stages: initiation, formation of the initiation complex, and elongation. Initiation requires the assembly of pre-replication complexes containing ORC, Cdc6, Cdt1 and MCM proteins. In S phase, Cdc45 and GINS are recruited to form the initiation complex. Elongation proceeds bidirectionally from replication forks, with leading strand synthesis continuous and lagging strand discontinuous via Okazaki fragments. Replication terminates at telomeres.
Gene silencing, also known as post-transcriptional gene silencing (PTGS), occurs when a gene is switched off by mechanisms other than mutation. It was first observed when an attempt to overexpress a pigment gene in petunia resulted in loss of pigment. This was due to co-suppression of both the endogenous gene and transgene. PTGS can occur via transcriptional gene silencing (TGS) or post-transcriptional gene silencing (PTGS) where mRNA is degraded. PTGS involves double-stranded RNA triggering cleavage and degradation of homologous mRNA through the RNA interference (RNAi) pathway, which involves dicer, siRNAs, and RISC complex.
Post-transcriptional modifications are important processes that convert primary transcript RNA into mature RNA. These modifications include 5' capping, 3' polyadenylation, and splicing of introns in eukaryotes. The modifications help make RNA molecules recognizable for translation and increase protein synthesis efficiency by removing non-coding regions. Different types of RNA undergo specific processing pathways involving nucleases, snoRNAs and other protein complexes.
DNA is constantly damaged by cellular metabolism, environmental factors like UV light, and replication errors. To prevent mutations, cells have direct damage reversal and excision repair mechanisms. Direct reversal uses enzymes like photolyases and alkyltransferases to directly restore damaged bases. Excision repair involves removing the damaged segment via pathways like base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR). BER repairs single base changes while NER excises oligonucleotides up to 30 bases. MMR corrects errors made during replication. Defects in these pathways are associated with cancers and genetic disorders like xeroderma pigmentosum.
This document summarizes different types of DNA repair mechanisms including base excision repair, nucleotide excision repair, and their mechanisms in E. coli and humans. It also discusses short patch and long patch base excision repair, and conditions like xeroderma pigmentosum that arise from defects in nucleotide excision repair.
Bio305 Lecture on Gene Regulation in Bacterial PathogensMark Pallen
This document summarizes the regulation of bacterial virulence gene expression. It discusses the hierarchical regulation of genes from the DNA to post-translational level. Key topics covered include transcription factors, operons, two-component systems, quorum sensing, and methods to study virulence gene expression such as reporter gene fusions, chromatin immunoprecipitation, and microarrays. The goal is to provide an overview of the complex regulatory networks that control bacterial pathogenesis.
Introduction
Components of binary vector
Development of binary vector system
Properties of binary vector
Types of binary vector
Plant transformation using binary vector
Advantage of using binary vector
Conclusion
References
This document discusses extrachromosomal DNA replication in prokaryotes and eukaryotes. In prokaryotes, extrachromosomal DNA is primarily found in plasmids. Plasmids replicate via rolling circle, iteron-regulated, or RNA-regulated mechanisms. In eukaryotes, extrachromosomal DNA is found in mitochondria and chloroplasts. Mitochondrial DNA replicates via a strand displacement model using DNA polymerase gamma and other specialized replication factors. Chloroplast DNA replication shares similarities but uses its own distinct replication proteins.
"Introns: Structure and Functions" during November, 2011 (Friday Seminar activity, Department of Biotechnology, University of Agricultural Sciences, Dharwad, Karnataka) by Yogesh S Bhagat (Ph D Scholar)
transcription activators, repressors, & control RNA splicing, procesing and e...ranjithahb ranjithahbhb
RNA processing involves several steps to convert primary transcripts into mature mRNA in eukaryotic cells. These include 5' capping, 3' cleavage and polyadenylation, and RNA splicing. RNA splicing involves two transesterification reactions that remove introns and join exons. Alternative splicing allows a single gene to produce multiple protein variants. Eukaryotic gene expression is regulated by transcriptional activators and repressors that bind cis-regulatory elements like promoters and enhancers. Activators recruit transcriptional machinery while repressors inhibit transcription. Chromatin structure also influences transcription with acetylation associated with active genes.
1. Beadle and Tatum's experiments with the fungus Neurospora crassa supported the "one gene-one enzyme hypothesis" which stated that each gene controls the production of a specific enzyme.
2. By inducing mutations in Neurospora and observing how they affected the fungus's ability to grow in different nutrient conditions, Beadle and Tatum were able to deduce biochemical pathways and determine that individual genes control steps in metabolism.
3. Their work provided evidence that genes control the synthesis of specific proteins and established the field of molecular genetics.
Relaxed plasmids & Regulation of copy numbersalvia16
Plasmids are classified as either stringent or relaxed based on their copy number in bacterial cells. Stringent plasmids exist in low copy numbers (<100 copies/cell) and rely on the bacterial genome for replication and segregation. Relaxed plasmids exist in high copy numbers (>100 copies/cell) and replicate independently of the bacterial genome. Relaxed plasmids include ColE1, which uses an antisense RNA mechanism to regulate its copy number based on plasmid concentration in the cell.
This document discusses site-specific recombination, including the structures and mechanisms involved. It describes two classes of recombinases - tyrosine recombinases and serine recombinases. Tyrosine recombinases involve cleavage of DNA through formation of a protein-DNA bond using a tyrosine residue. Serine recombinases utilize a phosphoserine bond between DNA and a conserved serine residue. The document provides examples of applications for site-specific recombination such as tracking cell lineage, altering gene expression, and targeted gene knockout.
This document summarizes molecular basis of mutations. It defines mutations as changes in genetic information and describes different types of mutations including point mutations, chromosomal mutations, germline mutations and somatic mutations. It also discusses various mutagens responsible for mutations like chemical mutagens such as alkylating agents, base analogs and reactive oxygen species, and physical mutagens like UV radiation and ionizing radiation. The mechanisms of different mutagens and types of mutations based on their phenotypic effects are also summarized.
DNA repair system lecture that were prepered by Ph.D. students Mohammed Mohsen and Aliaa Hashim at microbiology department / college of medicine / babylon university.
This presentation discusses the genetic code and how it translates DNA and RNA sequences into proteins. The genetic code is universal across all living organisms and consists of 64 codons composed of 3 nucleotides that correspond to 20 amino acids. Codons are classified as sense codons, which code for amino acids, or signal codons like initiation and termination codons. Anticodons on tRNAs pair with mRNA codons to recognize and translate the codons. The genetic code is non-overlapping, degenerate, and Francis Crick's wobble hypothesis explains the pattern of degeneracy by proposing the third position in the anticodon is not as specific.
The genetic code is composed of triplets of nucleotide bases that correspond to specific amino acids. There are 64 possible codon combinations from sequences of the 4 nucleotide bases, with 61 coding for 20 amino acids and 3 serving as stop codons. The genetic code is universal across all living organisms, specifying the same amino acids for each codon. It is read in sets of 3 bases moving in the 5' to 3' direction on mRNA, and mutations in the code can result in silent, missense, nonsense, or frameshift changes to the specified protein.
Regulation of eukaryotic gene expressionMd Murad Khan
The document discusses various mechanisms of regulating gene expression in eukaryotes. It explains that regulation can occur at multiple levels, including DNA, transcription, mRNA processing, and protein synthesis. Key points include: (1) Regulation allows adaptation and cellular differentiation; (2) In eukaryotes, transcription and translation are separated, allowing more complex regulation; (3) Regulation mechanisms include controlling chromatin structure, transcription initiation, mRNA splicing/stability, and protein modifications. Environmental factors like heat and hormones can also induce gene expression changes through transcription factors.
The document summarizes transcription and RNA processing in cells. There is a two step process of transcription and translation required for protein synthesis. Transcription involves synthesizing RNA from a DNA template in the nucleus. Translation occurs in the cytoplasm and converts mRNA into a polypeptide chain. Eukaryotic mRNA undergoes processing including 5' capping, polyadenylation, and splicing of introns from exons before it can be translated. Prokaryotic transcription initiation and termination differ from eukaryotes and involve RNA polymerase binding promoters and terminator sequences.
Transcription and synthesis of different RNAs
Processing of RNA transcript
Catalytic RNA
RNA splicing and Spliceosome
Transport of RNA through nuclear pore
Translation and polypeptide synthesis
Posttranslational modification
Protein trafficking and degradation
Antibiotics and inhibition of protein synthesis.
The mitochondrion is a membrane-bound organelle found in eukaryotic cells. It has an outer membrane, intermembrane space, inner membrane, cristae (folds in the inner membrane), and matrix. The inner membrane contains proteins involved in oxidative phosphorylation and ATP synthesis. Mitochondria contain their own circular DNA separate from the cell's nuclear DNA. Chloroplasts are similar organelles found in plant cells that conduct photosynthesis, and also contain their own DNA.
The document summarizes the spliceosome-mediated RNA splicing mechanism. It discusses how short RNA molecules called snRNAs (U1, U2, U4, U5, U6) associate with proteins to form snRNPs. These snRNPs bind to pre-mRNA transcripts to form a series of complexes, the last being the spliceosome, where splicing reactions occur. The assembly process involves the formation of commitment complex E, pre-spliceosome complex A upon U2 binding, and spliceosome B1 upon U4/U6 and U5 binding. U1 is then released and U6 interacts with the 5' splice site in complex B2, bringing the 3' and 5' splice
This document summarizes different types of DNA repair mechanisms including base excision repair, nucleotide excision repair, and their mechanisms in E. coli and humans. It also discusses short patch and long patch base excision repair, and conditions like xeroderma pigmentosum that arise from defects in nucleotide excision repair.
Bio305 Lecture on Gene Regulation in Bacterial PathogensMark Pallen
This document summarizes the regulation of bacterial virulence gene expression. It discusses the hierarchical regulation of genes from the DNA to post-translational level. Key topics covered include transcription factors, operons, two-component systems, quorum sensing, and methods to study virulence gene expression such as reporter gene fusions, chromatin immunoprecipitation, and microarrays. The goal is to provide an overview of the complex regulatory networks that control bacterial pathogenesis.
Introduction
Components of binary vector
Development of binary vector system
Properties of binary vector
Types of binary vector
Plant transformation using binary vector
Advantage of using binary vector
Conclusion
References
This document discusses extrachromosomal DNA replication in prokaryotes and eukaryotes. In prokaryotes, extrachromosomal DNA is primarily found in plasmids. Plasmids replicate via rolling circle, iteron-regulated, or RNA-regulated mechanisms. In eukaryotes, extrachromosomal DNA is found in mitochondria and chloroplasts. Mitochondrial DNA replicates via a strand displacement model using DNA polymerase gamma and other specialized replication factors. Chloroplast DNA replication shares similarities but uses its own distinct replication proteins.
"Introns: Structure and Functions" during November, 2011 (Friday Seminar activity, Department of Biotechnology, University of Agricultural Sciences, Dharwad, Karnataka) by Yogesh S Bhagat (Ph D Scholar)
transcription activators, repressors, & control RNA splicing, procesing and e...ranjithahb ranjithahbhb
RNA processing involves several steps to convert primary transcripts into mature mRNA in eukaryotic cells. These include 5' capping, 3' cleavage and polyadenylation, and RNA splicing. RNA splicing involves two transesterification reactions that remove introns and join exons. Alternative splicing allows a single gene to produce multiple protein variants. Eukaryotic gene expression is regulated by transcriptional activators and repressors that bind cis-regulatory elements like promoters and enhancers. Activators recruit transcriptional machinery while repressors inhibit transcription. Chromatin structure also influences transcription with acetylation associated with active genes.
1. Beadle and Tatum's experiments with the fungus Neurospora crassa supported the "one gene-one enzyme hypothesis" which stated that each gene controls the production of a specific enzyme.
2. By inducing mutations in Neurospora and observing how they affected the fungus's ability to grow in different nutrient conditions, Beadle and Tatum were able to deduce biochemical pathways and determine that individual genes control steps in metabolism.
3. Their work provided evidence that genes control the synthesis of specific proteins and established the field of molecular genetics.
Relaxed plasmids & Regulation of copy numbersalvia16
Plasmids are classified as either stringent or relaxed based on their copy number in bacterial cells. Stringent plasmids exist in low copy numbers (<100 copies/cell) and rely on the bacterial genome for replication and segregation. Relaxed plasmids exist in high copy numbers (>100 copies/cell) and replicate independently of the bacterial genome. Relaxed plasmids include ColE1, which uses an antisense RNA mechanism to regulate its copy number based on plasmid concentration in the cell.
This document discusses site-specific recombination, including the structures and mechanisms involved. It describes two classes of recombinases - tyrosine recombinases and serine recombinases. Tyrosine recombinases involve cleavage of DNA through formation of a protein-DNA bond using a tyrosine residue. Serine recombinases utilize a phosphoserine bond between DNA and a conserved serine residue. The document provides examples of applications for site-specific recombination such as tracking cell lineage, altering gene expression, and targeted gene knockout.
This document summarizes molecular basis of mutations. It defines mutations as changes in genetic information and describes different types of mutations including point mutations, chromosomal mutations, germline mutations and somatic mutations. It also discusses various mutagens responsible for mutations like chemical mutagens such as alkylating agents, base analogs and reactive oxygen species, and physical mutagens like UV radiation and ionizing radiation. The mechanisms of different mutagens and types of mutations based on their phenotypic effects are also summarized.
DNA repair system lecture that were prepered by Ph.D. students Mohammed Mohsen and Aliaa Hashim at microbiology department / college of medicine / babylon university.
This presentation discusses the genetic code and how it translates DNA and RNA sequences into proteins. The genetic code is universal across all living organisms and consists of 64 codons composed of 3 nucleotides that correspond to 20 amino acids. Codons are classified as sense codons, which code for amino acids, or signal codons like initiation and termination codons. Anticodons on tRNAs pair with mRNA codons to recognize and translate the codons. The genetic code is non-overlapping, degenerate, and Francis Crick's wobble hypothesis explains the pattern of degeneracy by proposing the third position in the anticodon is not as specific.
The genetic code is composed of triplets of nucleotide bases that correspond to specific amino acids. There are 64 possible codon combinations from sequences of the 4 nucleotide bases, with 61 coding for 20 amino acids and 3 serving as stop codons. The genetic code is universal across all living organisms, specifying the same amino acids for each codon. It is read in sets of 3 bases moving in the 5' to 3' direction on mRNA, and mutations in the code can result in silent, missense, nonsense, or frameshift changes to the specified protein.
Regulation of eukaryotic gene expressionMd Murad Khan
The document discusses various mechanisms of regulating gene expression in eukaryotes. It explains that regulation can occur at multiple levels, including DNA, transcription, mRNA processing, and protein synthesis. Key points include: (1) Regulation allows adaptation and cellular differentiation; (2) In eukaryotes, transcription and translation are separated, allowing more complex regulation; (3) Regulation mechanisms include controlling chromatin structure, transcription initiation, mRNA splicing/stability, and protein modifications. Environmental factors like heat and hormones can also induce gene expression changes through transcription factors.
The document summarizes transcription and RNA processing in cells. There is a two step process of transcription and translation required for protein synthesis. Transcription involves synthesizing RNA from a DNA template in the nucleus. Translation occurs in the cytoplasm and converts mRNA into a polypeptide chain. Eukaryotic mRNA undergoes processing including 5' capping, polyadenylation, and splicing of introns from exons before it can be translated. Prokaryotic transcription initiation and termination differ from eukaryotes and involve RNA polymerase binding promoters and terminator sequences.
Transcription and synthesis of different RNAs
Processing of RNA transcript
Catalytic RNA
RNA splicing and Spliceosome
Transport of RNA through nuclear pore
Translation and polypeptide synthesis
Posttranslational modification
Protein trafficking and degradation
Antibiotics and inhibition of protein synthesis.
The mitochondrion is a membrane-bound organelle found in eukaryotic cells. It has an outer membrane, intermembrane space, inner membrane, cristae (folds in the inner membrane), and matrix. The inner membrane contains proteins involved in oxidative phosphorylation and ATP synthesis. Mitochondria contain their own circular DNA separate from the cell's nuclear DNA. Chloroplasts are similar organelles found in plant cells that conduct photosynthesis, and also contain their own DNA.
The document summarizes the spliceosome-mediated RNA splicing mechanism. It discusses how short RNA molecules called snRNAs (U1, U2, U4, U5, U6) associate with proteins to form snRNPs. These snRNPs bind to pre-mRNA transcripts to form a series of complexes, the last being the spliceosome, where splicing reactions occur. The assembly process involves the formation of commitment complex E, pre-spliceosome complex A upon U2 binding, and spliceosome B1 upon U4/U6 and U5 binding. U1 is then released and U6 interacts with the 5' splice site in complex B2, bringing the 3' and 5' splice
آلاف البروتينات
تشارك في تفاعل داخل الخلية
وهى وسيلة الكائن الحي
لتنظيم التفاعل والنشاط
تفاعل البروتينات منظم تنظيم فائق
أحد أهم آليات التنظيم فسفرة البروتين العكسية
تعريف عدد كبير من عائلات الجينات التي تنظم نمو الخلية وانقسامها
اضطراب في واحد
أو عدد من الانكوجينات
يؤدى إلى تحولات في الخلية الطبيعية
إلى خليه سرطانية تؤدى إلى السرطان
مايكل بشوب هارولد فرمس
استخدما انكوجينات مسرطنه لفيروسات الرترو
لتحديد أو لتعريف الإنكوجينات
التي تنظم النمو في الخلية الطبيعية