Dna replication
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DNA replication is the process by which DNA copies its genetic material to produce two identical copies. There are three models of DNA replication, and the semiconservative model is accepted. DNA replication involves initiation, elongation, and termination steps. Initiation involves assembly of the replication fork at the origin of replication. In elongation, the parental strands unwind and daughter strands are synthesized by addition of bases. Termination occurs when the duplicated chromosomes separate, resulting in two identical copies of DNA.
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DNA RECOMBINATION
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MECHANISM OF DNA RECOMBINATION
TYPES OF RECOMBINATION
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Dna replication
DNA replication is the process by which DNA copies itself for transmission to daughter cells. In the late 1950s, three models were proposed for how DNA replicates: conservative, semi-conservative, and dispersive. Experiments showed that the semi-conservative model is correct, where each parental DNA strand acts as a template to replicate a new partner strand. DNA replication requires DNA and RNA polymerases, helicase, topoisomerases, primase, ligase and other proteins. It occurs through initiation, elongation and termination steps in both prokaryotes and eukaryotes, though eukaryotes have multiple replication origins and use RNA primers on the lagging strand.
Central dogma
This document provides an overview of the central dogma of biology and DNA replication. It begins by defining the central dogma as the flow of genetic information from DNA to RNA to proteins. It then discusses the four requirements for DNA to be the genetic material and explains DNA replication through semi-conservative replication and starting at the origin. The basics of transcription and translation are also summarized, including the components and steps of each process.
Dna replication prokaryotes
DNA replication in prokaryotes occurs through a semi-conservative process where each daughter cell inherits one old and one new DNA strand. Replication begins at the origin of replication and proceeds bidirectionally. It involves three main stages - initiation, elongation, and termination. Initiation requires unwinding of the DNA duplex by helicase at the origin. Elongation is carried out by DNA polymerase III which synthesizes new DNA strands along the leading strand continuously and in short fragments along the lagging strand. Termination occurs when the replication forks from opposite directions meet.
PROKARYOTIC DNA REPLICATION PRESENTATION
Prokaryotic DNA replication occurs through a semiconservative process involving three main steps: initiation, elongation, and termination. Initiation begins with unwinding of the DNA at the origin of replication by helicase. Elongation then takes place as DNA polymerase adds nucleotides to form new strands, with leading strand synthesis occurring continuously and lagging strand in fragments. Termination occurs when the replication forks from opposite directions meet and are halted by tus-ter complexes, separating the duplicated chromosomes.
Dna replication in prokaryotes
Introduction to Replication, Replication process in Prokaryotes
Proposed models of replication,
Semi-conservative method by meselson and sthal
DNA replication
The document summarizes DNA replication. It describes that DNA replication produces two identical copies of DNA from one original molecule through a semi-conservative process. This involves unwinding of DNA at origins of replication by helicase to form replication forks that grow bidirectionally. DNA polymerase then synthesizes new strands using the original strands as templates. Replication occurs through initiation, elongation, and termination steps mediated by various proteins at the replication fork. The Meselson-Stahl experiment provided evidence that DNA replication is semi-conservative through density gradient centrifugation of parental and progeny DNA.
Central dogma of molecular biology
This ppt covers:
Central dogma, discoverer of central dogma, Reason why its called central dogma, DNA, RNA, Protein, functions of protein, Types of RNA, DNA replication, Protein synthesis, Transcription, Translation, Exceptions of central dogma, Reverse transcription , prions, genetic code, mutation with types and causes
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II)BASE EXCISION REPAIR,
III)NUCLEOTIDE EXCISION REPAIR,
IV)MISMATCH REPAIR,
V)RECOMBINATION REPAIR,
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DNA RECOMBINATION
INTRODUCTION
MECHANISM OF DNA RECOMBINATION
TYPES OF RECOMBINATION
I) HOMOLOGOUS RECOMBINATION
MODELS FOR HOMOLOGOUS RECOMBINATION:-
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II)MESSELSON AND RADDING MODEL,
III)DOUBLE STRAND BREAK MODEL,
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II) NON-HOMOLOGOUS RECOMBINATION,
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Dna replication
DNA replication is the process by which DNA copies itself for transmission to daughter cells. In the late 1950s, three models were proposed for how DNA replicates: conservative, semi-conservative, and dispersive. Experiments showed that the semi-conservative model is correct, where each parental DNA strand acts as a template to replicate a new partner strand. DNA replication requires DNA and RNA polymerases, helicase, topoisomerases, primase, ligase and other proteins. It occurs through initiation, elongation and termination steps in both prokaryotes and eukaryotes, though eukaryotes have multiple replication origins and use RNA primers on the lagging strand.
Central dogma
This document provides an overview of the central dogma of biology and DNA replication. It begins by defining the central dogma as the flow of genetic information from DNA to RNA to proteins. It then discusses the four requirements for DNA to be the genetic material and explains DNA replication through semi-conservative replication and starting at the origin. The basics of transcription and translation are also summarized, including the components and steps of each process.
Dna replication prokaryotes
DNA replication in prokaryotes occurs through a semi-conservative process where each daughter cell inherits one old and one new DNA strand. Replication begins at the origin of replication and proceeds bidirectionally. It involves three main stages - initiation, elongation, and termination. Initiation requires unwinding of the DNA duplex by helicase at the origin. Elongation is carried out by DNA polymerase III which synthesizes new DNA strands along the leading strand continuously and in short fragments along the lagging strand. Termination occurs when the replication forks from opposite directions meet.
PROKARYOTIC DNA REPLICATION PRESENTATION
Prokaryotic DNA replication occurs through a semiconservative process involving three main steps: initiation, elongation, and termination. Initiation begins with unwinding of the DNA at the origin of replication by helicase. Elongation then takes place as DNA polymerase adds nucleotides to form new strands, with leading strand synthesis occurring continuously and lagging strand in fragments. Termination occurs when the replication forks from opposite directions meet and are halted by tus-ter complexes, separating the duplicated chromosomes.
Dna replication in prokaryotes
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Proposed models of replication,
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DNA replication
The document summarizes DNA replication. It describes that DNA replication produces two identical copies of DNA from one original molecule through a semi-conservative process. This involves unwinding of DNA at origins of replication by helicase to form replication forks that grow bidirectionally. DNA polymerase then synthesizes new strands using the original strands as templates. Replication occurs through initiation, elongation, and termination steps mediated by various proteins at the replication fork. The Meselson-Stahl experiment provided evidence that DNA replication is semi-conservative through density gradient centrifugation of parental and progeny DNA.
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Central dogma, discoverer of central dogma, Reason why its called central dogma, DNA, RNA, Protein, functions of protein, Types of RNA, DNA replication, Protein synthesis, Transcription, Translation, Exceptions of central dogma, Reverse transcription , prions, genetic code, mutation with types and causes
Replication In Eukaryotes and Prokaryotes
Replication Introduction , DNA replicating Models , Meselson and Stahl Experiments , Circuler Model of DNA replication , Replication in Prokaryotes , Replication In Eukaryotes , Comparison Between Prokaryotes and Eukaryotes Replicaton and PCR (Polymerease Chain Reaction)
DNA Replication -
1. DNA replication begins with the unwinding of the DNA double helix by the helicase enzyme. This exposes the two strands of DNA to serve as templates for DNA synthesis.
2. RNA primers are synthesized by the primase enzyme and DNA polymerase adds complementary nucleotides to the 3' end of each primer, elongating it into DNA.
3. The leading strand is synthesized continuously in the 5' to 3' direction while the lagging strand is synthesized in fragments called Okazaki fragments which are later joined by DNA ligase.
4. Several enzymes are involved including DNA polymerase, ligase, helicase, topoisomerase and others to accurately and efficiently copy DNA. DNA replication ensures faithful transmission of
Tryptophan operon
The tryptophan operon regulates the biosynthesis of tryptophan in E. coli through transcriptional attenuation and repression. It contains five genes encoding the enzymes needed to synthesize tryptophan. When tryptophan levels are high, the tryptophan repressor binds to the operator site, preventing transcription. Additionally, a regulatory region can form a terminator stem-loop structure to halt transcription if tryptophan tRNA levels are high during translation of the leader mRNA sequence. However, if tryptophan levels are low, the terminator structure does not form and transcription of the operon proceeds.
Dna repair
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.
Genetic recombination mechanism
Lecture slides on genetic recombination for anyone who is interested in molecular biology or who need to study genetics aspects of biology.
Dna replication in eukaryotes
DNA replication in eukaryotes occurs semi-conservatively, with each parental DNA strand serving as a template to create new daughter strands. It begins at origins of replication and proceeds bidirectionally. Enzymes such as helicase unwind the DNA double helix, while DNA polymerase adds complementary nucleotides to the leading and lagging strands. The lagging strand is synthesized discontinuously in short segments called Okazaki fragments. Telomeres protect chromosome ends from degradation during replication, and the telomerase enzyme maintains telomere length.
presentation on eukaryotic dna replication
Eukaryotic DNA replication occurs in the cell nucleus and involves multiple protein complexes. It begins with the assembly of pre-replication complexes at origins of replication during G1 phase. During S phase, these complexes are activated by cyclin-dependent kinases and Dbf4-dependent kinases to initiate bidirectional replication forks. Leading strand synthesis is continuous while lagging strand occurs discontinuously in short Okazaki fragments. Replication terminates once the replication forks from opposing origins meet.
Replication of the Ends of Eukaryotic Chromosome - Role of Telomerase
Telomeres are repetitive DNA sequences located at the ends of chromosomes that protect the ends from deterioration. They are maintained by the enzyme telomerase, which replenishes telomere sequences lost during DNA replication to prevent shortening of chromosomes. Telomerase contains an RNA template complementary to telomeric repeats and adds telomeric sequences to chromosome ends. While most somatic cells do not have sufficient telomerase to maintain telomere length indefinitely, cancer and stem cells express high levels of telomerase allowing unlimited division.
Central dogma
The central dogma describes the flow of genetic information from DNA to RNA to protein. DNA is first replicated to produce two identical DNA molecules. Transcription then produces mRNA from DNA, which differs in that only one DNA strand is used as a template. Translation follows, using the mRNA to direct protein synthesis on ribosomes with the help of tRNA. Mutations can occur in genes and chromosomes, altering DNA sequences and potentially changing protein functions or structures. Common gene mutations include substitutions, insertions, deletions, duplications, and frameshifts, while chromosome mutations involve translocations, deletions, duplications, inversions, and isochromosomes.
Various model of DNA replication
1. There are four main models of DNA replication: rolling circle replication, theta replication, bidirectional replication of linear DNA, and telomere replication.
2. Rolling circle replication involves nicking circular DNA and using one strand as a template to produce multiple copies of the original circular DNA.
3. Theta replication occurs in prokaryotes and involves unwinding circular DNA at an origin of replication and replicating bi-directionally to form a theta-shaped structure.
4. Bidirectional replication of linear DNA involves unwinding DNA at origins of replication and using leading and lagging strand synthesis to replicate in both directions until the ends of the linear genome are reached.
Replication in Bacteria.pptx
DNA replication in bacteria occurs through a semiconservative process whereby the parental double-stranded DNA separates and each strand serves as a template for synthesis of a new complementary strand. Meselson and Stahl's experiment provided evidence that replication occurs through this semiconservative model. DNA replication involves multiple enzymes that work together at the replication fork, including DNA polymerase III, helicase, primase, ligase, and topoisomerases. Replication initiates at the origin of replication and proceeds bidirectionally until termination is complete.
Replication in eukaryotes
This document summarizes DNA replication in eukaryotic cells. It describes that replication occurs through replicons to overcome the slower polymerases. Replication is initiated at specific sites called autonomous replicating sequences (ARS) where the origin recognition complex (ORC) binds. Elongation uses DNA polymerases α, δ, and ε and occurs semi-discontinuously with Okazaki fragments on the lagging strand. Termination involves removing RNA primers with RNase H and sealing fragments with DNA ligase. Multiple enzymes are involved in each phase including MCM helicase, primase, DNA ligase, and DNA polymerases.
Eukaryotic DNA replication
Eukaryotic DNA replicationMarudhar Kesari Jain College for Women Vaniyambadi - 635 751, Tamil Nadu, INDIA.
The document summarizes eukaryotic DNA replication. It discusses that DNA replication in eukaryotes is more complex than prokaryotes due to larger genome size and chromatin packaging. The key stages of eukaryotic replication are similar to prokaryotes, including origin of replication, formation of replication forks, semiconservative replication and synthesis of leading and lagging strands. However, eukaryotic replication involves additional proteins and is slower due to chromatin remodeling required to access DNA.DNA Replication in eukaryotes and prokaryotes
1. DNA replication is the process by which daughter DNA molecules are synthesized from a parental DNA template. It ensures the genetic information is transferred to the next generation with high fidelity.
2. Replication occurs semi-conservatively such that each new double helix contains one strand from the original parent DNA and one newly synthesized strand. It also occurs bidirectionally from an origin of replication.
3. DNA polymerases are the key enzymes that catalyze DNA synthesis. Other important enzymes and proteins include primase, helicase, topoisomerase, ligase, and single-stranded DNA binding proteins. Together they facilitate the initiation, elongation and termination of DNA replication.
DNA replication in Prokaryotes
DNA REPLICATION: Semi conservative replication, Enzymes involved in DNA replication, Initiation, Elongation and Termination.
Replicon
This document discusses replicons and the enzymes involved in DNA replication. It defines a replicon as a DNA molecule containing an origin of replication essential for initiating replication. Replicons can be linear or circular and contain initiator and termination sequences. The number of replicons per chromosome depends on its size. Various enzymes involved in replication include helicases to unwind DNA, primase to create RNA primers, DNA polymerases for DNA synthesis, ligase to join DNA fragments, and topoisomerases to relieve torsional stress. Replication proceeds bidirectionally from origins in prokaryotes and from multiple origins in eukaryotes in a tightly regulated process.
Recombination
recombination
types of recombination
models of recombination
biological roles of recombination
Dna replication in prokaryotes
This document summarizes DNA replication in prokaryotes. It begins by introducing DNA and its role in encoding genetic instructions. It then describes the general features of DNA replication, including that it is semi-conservative and bidirectional from the origin of replication. It discusses the various enzymes involved, including DNA polymerase, helicase, and ligase. It provides details on the three stages of replication in prokaryotes - initiation, elongation, and termination. Initiation begins at the origin of replication with unwinding, elongation involves continuous leading and discontinuous lagging strand synthesis, and termination occurs at terminus sequences.
Gene regulation in prokaryotes
Most bacteria are free-living organisms that grow by increasing
in mass and then divide by binary fission.
Growth and division are controlled by genes, the expression
of which must be regulated appropriately. Genes
whose activity is controlled in response to the needs of a
cell or organism are called regulated genes. All organisms
also have a large number of genes whose products
are essential to the normal functioning of a growing and
dividing cell, no matter what the conditions are. These
genes are always active in growing cells and are known as
constitutive genes or housekeeping genes; examples include
genes that code for the enzymes needed for protein
synthesis and glucose metabolism. Note that all genes are
regulated on some level. If normal cell function is impaired
for some reason, the expression of all genes, including
constitutive genes, is reduced by regulatory
mechanisms. Thus, the distinction between regulated
and constitutive genes is somewhat arbitrary.
Transcription in prokaryotes
This document discusses the central dogma of biology and the process of transcription. It describes the three main steps of transcription - initiation, elongation, and termination. Initiation involves the RNA polymerase binding to the promoter sequence on DNA and separating the DNA strands to form an open complex. Elongation is the addition of nucleotides to synthesize RNA. Termination can occur via either Rho-independent or Rho-dependent mechanisms, with the former utilizing a terminator sequence and hairpin structure in the RNA and the latter involving the Rho protein.
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Replication In Eukaryotes and Prokaryotes
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DNA Replication -
1. DNA replication begins with the unwinding of the DNA double helix by the helicase enzyme. This exposes the two strands of DNA to serve as templates for DNA synthesis.
2. RNA primers are synthesized by the primase enzyme and DNA polymerase adds complementary nucleotides to the 3' end of each primer, elongating it into DNA.
3. The leading strand is synthesized continuously in the 5' to 3' direction while the lagging strand is synthesized in fragments called Okazaki fragments which are later joined by DNA ligase.
4. Several enzymes are involved including DNA polymerase, ligase, helicase, topoisomerase and others to accurately and efficiently copy DNA. DNA replication ensures faithful transmission of
Tryptophan operon
The tryptophan operon regulates the biosynthesis of tryptophan in E. coli through transcriptional attenuation and repression. It contains five genes encoding the enzymes needed to synthesize tryptophan. When tryptophan levels are high, the tryptophan repressor binds to the operator site, preventing transcription. Additionally, a regulatory region can form a terminator stem-loop structure to halt transcription if tryptophan tRNA levels are high during translation of the leader mRNA sequence. However, if tryptophan levels are low, the terminator structure does not form and transcription of the operon proceeds.
Dna repair
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.
Genetic recombination mechanism
Lecture slides on genetic recombination for anyone who is interested in molecular biology or who need to study genetics aspects of biology.
Dna replication in eukaryotes
DNA replication in eukaryotes occurs semi-conservatively, with each parental DNA strand serving as a template to create new daughter strands. It begins at origins of replication and proceeds bidirectionally. Enzymes such as helicase unwind the DNA double helix, while DNA polymerase adds complementary nucleotides to the leading and lagging strands. The lagging strand is synthesized discontinuously in short segments called Okazaki fragments. Telomeres protect chromosome ends from degradation during replication, and the telomerase enzyme maintains telomere length.
presentation on eukaryotic dna replication
Eukaryotic DNA replication occurs in the cell nucleus and involves multiple protein complexes. It begins with the assembly of pre-replication complexes at origins of replication during G1 phase. During S phase, these complexes are activated by cyclin-dependent kinases and Dbf4-dependent kinases to initiate bidirectional replication forks. Leading strand synthesis is continuous while lagging strand occurs discontinuously in short Okazaki fragments. Replication terminates once the replication forks from opposing origins meet.
Replication of the Ends of Eukaryotic Chromosome - Role of Telomerase
Telomeres are repetitive DNA sequences located at the ends of chromosomes that protect the ends from deterioration. They are maintained by the enzyme telomerase, which replenishes telomere sequences lost during DNA replication to prevent shortening of chromosomes. Telomerase contains an RNA template complementary to telomeric repeats and adds telomeric sequences to chromosome ends. While most somatic cells do not have sufficient telomerase to maintain telomere length indefinitely, cancer and stem cells express high levels of telomerase allowing unlimited division.
Central dogma
The central dogma describes the flow of genetic information from DNA to RNA to protein. DNA is first replicated to produce two identical DNA molecules. Transcription then produces mRNA from DNA, which differs in that only one DNA strand is used as a template. Translation follows, using the mRNA to direct protein synthesis on ribosomes with the help of tRNA. Mutations can occur in genes and chromosomes, altering DNA sequences and potentially changing protein functions or structures. Common gene mutations include substitutions, insertions, deletions, duplications, and frameshifts, while chromosome mutations involve translocations, deletions, duplications, inversions, and isochromosomes.
Various model of DNA replication
1. There are four main models of DNA replication: rolling circle replication, theta replication, bidirectional replication of linear DNA, and telomere replication.
2. Rolling circle replication involves nicking circular DNA and using one strand as a template to produce multiple copies of the original circular DNA.
3. Theta replication occurs in prokaryotes and involves unwinding circular DNA at an origin of replication and replicating bi-directionally to form a theta-shaped structure.
4. Bidirectional replication of linear DNA involves unwinding DNA at origins of replication and using leading and lagging strand synthesis to replicate in both directions until the ends of the linear genome are reached.
Replication in Bacteria.pptx
DNA replication in bacteria occurs through a semiconservative process whereby the parental double-stranded DNA separates and each strand serves as a template for synthesis of a new complementary strand. Meselson and Stahl's experiment provided evidence that replication occurs through this semiconservative model. DNA replication involves multiple enzymes that work together at the replication fork, including DNA polymerase III, helicase, primase, ligase, and topoisomerases. Replication initiates at the origin of replication and proceeds bidirectionally until termination is complete.
Replication in eukaryotes
This document summarizes DNA replication in eukaryotic cells. It describes that replication occurs through replicons to overcome the slower polymerases. Replication is initiated at specific sites called autonomous replicating sequences (ARS) where the origin recognition complex (ORC) binds. Elongation uses DNA polymerases α, δ, and ε and occurs semi-discontinuously with Okazaki fragments on the lagging strand. Termination involves removing RNA primers with RNase H and sealing fragments with DNA ligase. Multiple enzymes are involved in each phase including MCM helicase, primase, DNA ligase, and DNA polymerases.
Eukaryotic DNA replication
Eukaryotic DNA replicationMarudhar Kesari Jain College for Women Vaniyambadi - 635 751, Tamil Nadu, INDIA.
The document summarizes eukaryotic DNA replication. It discusses that DNA replication in eukaryotes is more complex than prokaryotes due to larger genome size and chromatin packaging. The key stages of eukaryotic replication are similar to prokaryotes, including origin of replication, formation of replication forks, semiconservative replication and synthesis of leading and lagging strands. However, eukaryotic replication involves additional proteins and is slower due to chromatin remodeling required to access DNA.DNA Replication in eukaryotes and prokaryotes
1. DNA replication is the process by which daughter DNA molecules are synthesized from a parental DNA template. It ensures the genetic information is transferred to the next generation with high fidelity.
2. Replication occurs semi-conservatively such that each new double helix contains one strand from the original parent DNA and one newly synthesized strand. It also occurs bidirectionally from an origin of replication.
3. DNA polymerases are the key enzymes that catalyze DNA synthesis. Other important enzymes and proteins include primase, helicase, topoisomerase, ligase, and single-stranded DNA binding proteins. Together they facilitate the initiation, elongation and termination of DNA replication.
DNA replication in Prokaryotes
DNA REPLICATION: Semi conservative replication, Enzymes involved in DNA replication, Initiation, Elongation and Termination.
Replicon
This document discusses replicons and the enzymes involved in DNA replication. It defines a replicon as a DNA molecule containing an origin of replication essential for initiating replication. Replicons can be linear or circular and contain initiator and termination sequences. The number of replicons per chromosome depends on its size. Various enzymes involved in replication include helicases to unwind DNA, primase to create RNA primers, DNA polymerases for DNA synthesis, ligase to join DNA fragments, and topoisomerases to relieve torsional stress. Replication proceeds bidirectionally from origins in prokaryotes and from multiple origins in eukaryotes in a tightly regulated process.
Recombination
recombination
types of recombination
models of recombination
biological roles of recombination
Dna replication in prokaryotes
This document summarizes DNA replication in prokaryotes. It begins by introducing DNA and its role in encoding genetic instructions. It then describes the general features of DNA replication, including that it is semi-conservative and bidirectional from the origin of replication. It discusses the various enzymes involved, including DNA polymerase, helicase, and ligase. It provides details on the three stages of replication in prokaryotes - initiation, elongation, and termination. Initiation begins at the origin of replication with unwinding, elongation involves continuous leading and discontinuous lagging strand synthesis, and termination occurs at terminus sequences.
Gene regulation in prokaryotes
Most bacteria are free-living organisms that grow by increasing
in mass and then divide by binary fission.
Growth and division are controlled by genes, the expression
of which must be regulated appropriately. Genes
whose activity is controlled in response to the needs of a
cell or organism are called regulated genes. All organisms
also have a large number of genes whose products
are essential to the normal functioning of a growing and
dividing cell, no matter what the conditions are. These
genes are always active in growing cells and are known as
constitutive genes or housekeeping genes; examples include
genes that code for the enzymes needed for protein
synthesis and glucose metabolism. Note that all genes are
regulated on some level. If normal cell function is impaired
for some reason, the expression of all genes, including
constitutive genes, is reduced by regulatory
mechanisms. Thus, the distinction between regulated
and constitutive genes is somewhat arbitrary.
Transcription in prokaryotes
This document discusses the central dogma of biology and the process of transcription. It describes the three main steps of transcription - initiation, elongation, and termination. Initiation involves the RNA polymerase binding to the promoter sequence on DNA and separating the DNA strands to form an open complex. Elongation is the addition of nucleotides to synthesize RNA. Termination can occur via either Rho-independent or Rho-dependent mechanisms, with the former utilizing a terminator sequence and hairpin structure in the RNA and the latter involving the Rho protein.
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There is a general assumption that intraspecific populations originating from relatively arid climates will be better adapted to cope with the expected increase in drought from climate change. For ecologically and economically important species, more comprehensive, genecological studies that utilize large distributions of populations and direct measures of traits associated with drought-resistance are needed to empirically support this assumption because of the implications for the natural or assisted regeneration of species. We conducted a space-for-time substitution, common garden experiment with 35 populations of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) growing at three test sites with distinct summer temperature and precipitation (referred to as ‘cool/moist’, ‘moderate’ or ‘warm/dry’) to test the hypotheses that 1) there is large genetic variation among populations and regions in traits associated with drought-resistance, 2) the patterns of genetic variation are related to the native source-climate of each population, in particular with summer temperature and precipitation, 3) the differences among populations and relationships with climate are stronger at the warm/dry test site owing to greater expression of drought-resistance traits (i.e. a genotype × environment interaction). During mid-summer 2012, we measured the rate of water loss after stomatal closure (transpirationmin), water deficit (% below turgid saturation), and specific leaf area (SLA, cm2g-1) on new growth of sapling branches. There was significant genetic variation in all plant traits, with populations originating from warmer and drier climates having greater drought-resistance (i.e., lower transpirationmin, water deficit and SLA), but these trends were most clearly expressed only at the warm/dry test site. Contrary to expectations, populations from cooler climates also had greater drought-resistance across all test sites. Multiple regression analysis indicated that Douglas-fir populations from regions with relatively cool winters and arid summers may be most adapted to cope with drought conditions that are expected in the future.
Turf Drough Tresistance
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R. serraj. Screening and trait based selection for drought resistance in rice
1. Screening and selection for drought resistance in rice requires understanding the target environment and type of drought stress.
2. The goal should be stable yield under drought. Screening methods need to create uniform and repeatable drought conditions to differentiate genotypes.
3. Field and irrigation management are critical to obtain reliable data from drought screening. No single screening procedure is appropriate for all situations.
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Drought and waterlogging are major abiotic stresses that limit the productivity of Brachiaria forage grasses. Little attention has been given to separate productivity under drought or waterlogging, from coping mechanisms in Brachiaria forage grasses. Wide phenotypic variation exists among Brachiaria grasses to cope with these stresses. This presentation will cover : 1) the current knowledge of morpho-physiological mechanisms and functional adaptations of Brachiaria spp cultivars to cope with these stresses and 2) the use of sensors and digital image analysis for the non-destructive and automated analysis of Brachiaria growth and performance at different time scales.
Genetically Modified Crop ( DROUGHT RESISTANCE CROP )
This document discusses genetically modified drought resistant crops. It begins by defining genetically modified crops as plants modified using genetic engineering to introduce new traits. It then discusses developing drought tolerant crops through conventional breeding and genetic engineering techniques. Conventional breeding is a slow process limited by available genes, while genetic engineering allows introducing genes controlling drought tolerance. The document provides examples of drought tolerance mechanisms in plants and genes introduced through genetic engineering to improve drought resistance in transgenic crops.
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This document discusses breeding for resistance to abiotic stresses like drought, salt, and cold in fruit crops. It provides information on the characteristics, effects, and mechanisms of different abiotic stresses. It also outlines strategies for breeding resistance, including selecting from cultivated varieties, landraces, and wild relatives. The key mechanisms of resistance include avoidance, tolerance, and acclimation. Traits like early maturity, reduced transpiration, and accumulating osmolytes can provide drought and salt resistance.
Genetically modified crops and food Security..scientific facts
Genetically modified crops can help increase food security in several ways:
1) They can increase yields through traits like insect resistance, herbicide tolerance, virus resistance, and drought tolerance. This helps increase food availability.
2) GM crops that are drought resistant or produce higher yields allow food to be grown in more difficult conditions, improving stability of food sources.
3) Some GM crops aim to directly enhance nutrition, such as golden rice which is engineered to produce higher amounts of vitamin A to address deficiencies.
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This presentation discusses the impact of drought on the people of Senegal and Sudan. Drought is a weather-related natural disaster that affects large regions for months or years by reducing food production and water supplies. While drought harms many communities, some individuals can benefit economically, such as sellers who can charge higher prices for scarce goods. The presentation examines the specific challenges faced in Senegal and Sudan, including problems securing clean water, impacts on daily life and food security, and effects on the global economy. Solutions proposed to address drought include building water pipes, planting more trees, and constructing dams to store rainwater.
PPT on drought in india
Drought is an extended period of deficient water supply caused by significantly below average precipitation. It can impact ecosystems, agriculture, and local economies. Some plant species have adaptations like reduced leaves or waxy coatings to tolerate drought. Past droughts in India have led to major famines and tens of millions of deaths in the 18th-20th centuries. Indian agriculture depends heavily on the summer monsoon, and monsoon failures can result in water shortages and below average crop yields in drought-prone regions.
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The document summarizes plant responses to different types of stress. It discusses how plants can avoid or tolerate stress through mechanisms like osmotic adjustment, accumulation of compatible solutes, and heat shock protein production. Stress can be biotic, imposed by other organisms, or abiotic arising from environmental deficits or excesses. Abiotic stresses discussed include drought, high salinity, temperature extremes, and oxidative stress from pollutants. Stress triggers changes in gene expression and metabolism that help plants withstand damaging conditions.
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This document discusses drought, including its types, causes, history, and effects. It defines drought as a prolonged period of abnormally low rainfall that results in water shortage. There are three main types of drought: meteorological, relating to low rainfall; hydrological, regarding low water levels in supplies; and agricultural, when not enough water is available for crops. Common causes include deficiencies in rain, soil erosion, global warming, deforestation. India experiences frequent droughts affecting over 70% of its cultivated land. Specific regions that are prone to drought are identified.
Plant stress responses
The document summarizes plant stress responses to both abiotic and biotic stresses. It discusses how plants detect stress signals and trigger responses across multiple levels, from gene expression changes to production of protective proteins and metabolites. Stress responses aim to acclimate the plant and prevent damage through avoidance, tolerance and adaptation mechanisms. Key responses include production of heat shock proteins under heat stress, osmolytes for drought and salt tolerance, and pathogenesis-related proteins and phytoalexins as antimicrobial defenses against pathogens.
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DNA replication (1).ppt
DNA replication involves unwinding the double helix at the replication fork, synthesizing new strands in a semi-conservative manner, and joining fragments. It is semi-conservative, with each parental strand serving as a template for a new daughter strand. Replication is bidirectional and occurs continuously on the leading strand but discontinuously on the lagging strand, which is synthesized in fragments called Okazaki fragments. The process involves initiation at the origin of replication, unwinding and stabilizing the strands, primer formation, strand elongation, fragment joining, and termination.
DNA replication.ppt
DNA replication involves unwinding the double helix at the replication fork, synthesizing new strands in the 5' to 3' direction, and joining fragments together. It is semi-conservative, with each parental strand serving as a template for a new complementary daughter strand. The leading strand copies continuously from the replication origin, while the lagging strand copies in short fragments that are later joined by DNA ligase. Various enzymes work together in this process, including helicase, gyrase, primase, DNA polymerase, and ligase to make an exact copy of the DNA molecule.
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DNA replication is the process by which a cell makes an identical copy of its DNA. It occurs semi-conservatively, with each original DNA strand serving as a template for the production of a new complementary strand. Replication initiates at an origin of replication and proceeds bidirectionally. In bacteria, the replication fork contains enzymes that unwind and separate the DNA strands. RNA primers are laid down and DNA polymerase extends DNA synthesis from the primers in the 5' to 3' direction on both the continuous leading and discontinuous lagging strands, generating Okazaki fragments. DNA ligase then seals the fragments together.
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DNA replication is the process by which a cell makes an identical copy of its DNA. It involves unwinding the double helix at an origin of replication and using each parental strand as a template to synthesize new daughter strands. This results in two identical copies of the DNA molecule. Replication is semi-conservative, meaning each new DNA molecule contains one original parental strand and one newly synthesized strand. It is also bidirectional and semi-discontinuous. The leading strand is copied continuously while the lagging strand is copied discontinuously in fragments that are later joined.
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This document discusses DNA replication in prokaryotes and eukaryotes. It provides an overview of the key steps and enzymes involved in DNA replication for both prokaryotes and eukaryotes. For prokaryotes, it describes initiation at the origin of replication involving DNA A protein, elongation by DNA polymerase III, and termination when replication forks meet. For eukaryotes, it outlines initiation involving pre-replication complexes, elongation involving leading and lagging strand synthesis, and the various enzymes involved such as DNA polymerases and helicases.
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The document discusses DNA replication. It begins by defining key terms like replication, transcription, translation and reverse transcription. It then explains the process of DNA replication in more detail over several sections. Replication involves parental DNA being used as a template to synthesize new daughter strands. This occurs through a semi-conservative process using enzymes like DNA polymerase and results in two identical copies of the original DNA.
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DNA replication is the process whereby a cell passes on its genetic material to its daughter cells. It involves DNA polymerase synthesizing new DNA strands using existing DNA as a template. There are several key steps and enzymes involved:
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Rolling circle mechanism ppt
Rolling circle replication is a process that can rapidly synthesize multiple copies of circular DNA or RNA molecules. It involves the unidirectional replication of circular nucleic acids. The process begins with an initiator protein nicking one strand of the circular DNA. DNA polymerase then uses the 3' end of the nicked strand to initiate replication, displacing the 5' end. Replication continues around the circle to produce a long concatemer of copies. The concatemer is then cleaved and ligated to form multiple double-stranded circular DNA molecules. Rolling circle replication is used by some viruses and plasmids to replicate their genomes and can be harnessed for applications like signal amplification in biosensing.
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DNA replication is a highly regulated process that exactly duplicates the genome during cell division. It involves unwinding of the DNA double helix at the origin of replication by helicase. Each single-stranded template is then used to synthesize a new complementary strand in the 5'-to-3' direction by DNA polymerase. The leading strand is replicated continuously while the lagging strand is replicated discontinuously in short segments called Okazaki fragments that are later joined by ligase. Several proteins and enzymes work together in a coordinated manner to ensure the genome is accurately duplicated and inherited by daughter cells.
Dna replication
DNA replication is the process by which DNA duplicates itself for transmission to new cells. It occurs during S phase of the cell cycle and involves unwinding the DNA double helix, exposing the bases. Enzymes then link complementary nucleotides to form new strands. There are three proposed models for how replication occurs - semi-conservative, conservative, and dispersive. Replication requires a set of proteins and enzymes and energy in the form of ATP. It has two basic steps - initiation and elongation - and two basic components - a template and primer.
DNA replication.pptx
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2. DNA polymerase requires an RNA primer to initiate DNA synthesis. Polymerase I then replaces the RNA primer with DNA and seals the nick with DNA ligase.
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DNA replication is the process by which a cell makes an identical copy of its DNA. It involves DNA polymerase enzymes that assemble new DNA strands using existing DNA as a template. There are four key steps:
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2. RNA primers are synthesized by primase and DNA polymerase extends the primers to replicate the leading strand continuously and lagging strand in fragments called Okazaki fragments.
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This document provides information about the central dogma of molecular biology and DNA replication. It begins with an overview of the central dogma, which describes how genetic information flows from DNA to RNA to protein. It then discusses DNA replication in detail, including that it is semiconservative, begins at an origin of replication, and proceeds bidirectionally. Replication of the leading strand is continuous while the lagging strand is replicated discontinuously in fragments called Okazaki fragments. The replication complex coordinates this process.
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The document discusses the central dogma of molecular biology, which states that DNA is transcribed into RNA and then translated into protein. It describes the process of DNA replication, including initiation, elongation, and termination. DNA replication is semiconservative and bidirectional, with the leading strand synthesized continuously and the lagging strand synthesized discontinuously in fragments. The mechanisms of DNA replication are largely similar between prokaryotes and eukaryotes.
Replication and gene exression
DNA replication and gene expression are the two main processes by which DNA is copied and expressed. DNA replication involves unwinding the parental DNA strands, synthesizing new complementary strands according to base pairing rules, resulting in two identical copies of the original DNA. Gene expression involves transcription of DNA into RNA and translation of RNA into protein. Transcription occurs in the nucleus and involves RNA polymerase making an RNA copy of a gene. The RNA then undergoes processing before being exported to the cytoplasm for translation by ribosomes into a polypeptide chain according to the genetic code.
Dna replication
DNA replication is the process where a double-stranded DNA molecule is copied to produce two identical copies. It occurs during the S phase of the cell cycle. The DNA double helix unwinds and each strand serves as a template for new partner strands. DNA polymerase adds complementary nucleotides to each new strand, building them from the 5' to 3' direction. The leading strand is synthesized continuously while the lagging strand is synthesized discontinuously in fragments called Okazaki fragments that are later joined together. This semiconservative process results in two double-stranded DNA molecules that are identical to the original DNA.
Dna replication
DNA replication is the process where a double-stranded DNA molecule is copied to produce two identical copies. It occurs during the S phase of the cell cycle. The DNA double helix unwinds and each strand serves as a template for new partner strands. DNA polymerase adds complementary nucleotides to each new strand, building them from the 5' to 3' direction. The leading strand is replicated continuously while the lagging strand is replicated in discontinuous fragments called Okazaki fragments that are later joined together.
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The document discusses bidirectional and rolling circular DNA replication. It begins by explaining that DNA replication is semi-conservative, with each new DNA molecule composed of one original strand and its complement. It then describes how in bidirectional replication, replication forks move in opposite directions from a single origin to copy both strands simultaneously. Rolling circular replication involves the continuous, unidirectional synthesis of multiple copies of a circular DNA or RNA genome through the sequential steps of initiation by introducing a nick, elongation by polymerase moving in a circle, and termination by cleaving the replicated strand.
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DNA replication is the process by which DNA makes a copy of itself during cell division.The separation of the two single strands of DNA creates a 'Y' shape called a replication 'fork'. The two separated strands will act as templates for making the new strands of DNA.
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1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...
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Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/Applied Science: Thermodynamics, Laws & Methodology.pdf
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
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ESPP presentation to EU Waste Water Network, 4th June 2024 “EU policies driving nutrient removal and recycling
and the revised UWWTD (Urban Waste Water Treatment Directive)”
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
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ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...
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Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
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In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.waterlessdyeingtechnolgyusing carbon dioxide chemicalspdf
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Dna replication
- 1. DNA Replication Presentation by: Md. Shabab Mehebub
- 2. DNA Replication • Copying genetic information for transmission to the next generation is called DNA replication.
- 4. Three model of DNA Replication • We will follow the Semiconsevative Model because it is accepted by everyone.
- 5. DNA Replication Steps: • Initiation – involves assembly of replication fork (bubble) at origin of replication • sequence of DNA found at a specific site • Elongation – Parental strands unwind and daughter strands are synthesized. – the addition of bases by proteins • Termination: – the duplicated chromosomes separate from each other. Now, there are two IDENTICAL copies of DNA. Segments of single-stranded DNA are called template strands. Copied strand is called the complement strand • LEADING STRAND: synthesized 5’ to 3’ in the direction of the replication fork movement. -continuous requires a single RNA primer • LAGGING STRAND: synthesized 5’ to 3’ in the opposite direction. – semidiscontinuous requires many RNA primers , DNA is synthesized in short fragments.
- 7. 3 Polymerase III Leading strand base pairs 5’ 5’ 3’ 3’ Supercoiled DNA relaxed by gyrase & unwound by helicase + proteins: Helicase + Initiator Proteins ATP SSB Proteins RNA Primer primase 2Polymerase III Lagging strand Okazaki Fragments 1 RNA primer replaced by polymerase I & gap is sealed by ligase Gyrase
- 9. Elongation DNA polymerase only adds nucleotides at the free 3’ end of NEW STRAND forming new DNA strands in the 5’ 3’ direction only…
- 10. DNA ligase seals the gaps between Okazaki fragments with a phosphodiester bond
- 11. Mistakes during Replication Polymerase uses its proofreading ability to cleave the phosphodiester bond of improper nucleotide