Nucleic acid carries genetic material part-1
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Nucleic acid carries genetic material (Griffith’s Hershey & Chase and Avery- Macleod-McCarty Experiment)
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transformation
This document discusses bacterial transformation, which is the process by which bacteria take up naked DNA from their environment. There are three main ways bacteria exchange DNA: conjugation, transduction, and transformation. Transformation occurs when bacteria take up free DNA from their surroundings. Some bacteria have the natural ability to undergo transformation, while others can be artificially induced to become competent through chemical treatments or electroporation. The document outlines the key steps and proteins involved in natural and artificial bacterial transformation.
Bacterial Conjugation
This document discusses genetic recombination in prokaryotes. It describes three main mechanisms of genetic recombination: transformation, transduction, and conjugation. Conjugation involves the transfer of DNA from one bacterium to another through direct cell-to-cell contact and requires a conjugative plasmid. The document then discusses bacterial conjugation in more detail, covering the history of its discovery, the roles of different plasmids, and the key steps and genes involved in the conjugation process. It also describes three main conjugative processes: F+ conjugation, Hfr conjugation, and resistant plasmid conjugation.
DNA as a genetic material
This document discusses DNA and RNA. It notes that DNA contains adenine, thymine, cytosine and guanine while RNA contains uracil instead of thymine. DNA exists as a double helix while RNA takes various shapes. The document also discusses Griffith's experiment which provided evidence that DNA is the genetic material by showing a heat-killed pathogenic pneumonia strain could transform a non-pathogenic strain to be pathogenic. Further experiments by Avery, Macleod and McCarthy proved the transforming principle was DNA. The document also discusses how experiments on tobacco mosaic virus provided evidence that RNA can act as the genetic material for some viruses.
RNA AS GENETIC MATERIAL
RNA plays important roles in coding, decoding, regulating, and expressing genes. Some viruses use RNA as their genetic material, including those that cause diseases like SARS, influenza, hepatitis C, and measles. Tobacco mosaic virus (TMV) was the first virus crystallized and shown through experiments to have RNA, not DNA, as its genetic material. When purified TMV RNA was inoculated into healthy tobacco plants, it caused lesions, demonstrating that the RNA alone carried the genetic information to cause infection.
Reverse Transcription of RNA
Reverse transcription of RNA is a process whereby RNA, typically messenger RNA is converted into complimentary DNA. The process was discovered by Howard Temin and John Baltimore when they observed that certain RNA viruses could revert to DNA. This was an important discovery that led to the discovery of enzymes classified as reverse transcriptases. Today Reverse Transcription is routinely applied in molecular biology laboratories to obtain the stable cDNA version of RNA for downstream analysis.
RNA SPLICING
RNA splicing is a process where introns are removed from precursor messenger RNA (pre-mRNA) and exons are joined together to produce mature mRNA. It occurs in the nucleus and is essential for eukaryotes to produce proteins. The spliceosome, a large complex of RNA and proteins, facilitates two transesterification reactions that remove introns and ligate exons. RNA splicing generates protein diversity through alternative splicing and is important for cellular functions and disease processes.
Charging of tRNA, Aminoacyl tRNA Synthetases
CBCS 4TH SEM ,
CHARGING, STRUCTURE AND FUNCTION OF tRNA,
AMINOACYL RNA SYNTHETASE(ASR) PROOFREADING AND EDITING
https://www.youtube.com/watch?v=YzOVMWYLiCE
Plasmid
This document provides an overview of plasmids. It defines plasmids as small, circular, extrachromosomal DNA molecules that can replicate independently in bacteria. Plasmids contain genes that provide benefits to bacteria like antibiotic resistance. They are transferred between bacteria through processes like transformation, transduction, and conjugation. Plasmids are classified based on their functions and are important tools in biotechnology as they allow cloning, protein production, and other applications.
Recommended
transformation
This document discusses bacterial transformation, which is the process by which bacteria take up naked DNA from their environment. There are three main ways bacteria exchange DNA: conjugation, transduction, and transformation. Transformation occurs when bacteria take up free DNA from their surroundings. Some bacteria have the natural ability to undergo transformation, while others can be artificially induced to become competent through chemical treatments or electroporation. The document outlines the key steps and proteins involved in natural and artificial bacterial transformation.
Bacterial Conjugation
This document discusses genetic recombination in prokaryotes. It describes three main mechanisms of genetic recombination: transformation, transduction, and conjugation. Conjugation involves the transfer of DNA from one bacterium to another through direct cell-to-cell contact and requires a conjugative plasmid. The document then discusses bacterial conjugation in more detail, covering the history of its discovery, the roles of different plasmids, and the key steps and genes involved in the conjugation process. It also describes three main conjugative processes: F+ conjugation, Hfr conjugation, and resistant plasmid conjugation.
DNA as a genetic material
This document discusses DNA and RNA. It notes that DNA contains adenine, thymine, cytosine and guanine while RNA contains uracil instead of thymine. DNA exists as a double helix while RNA takes various shapes. The document also discusses Griffith's experiment which provided evidence that DNA is the genetic material by showing a heat-killed pathogenic pneumonia strain could transform a non-pathogenic strain to be pathogenic. Further experiments by Avery, Macleod and McCarthy proved the transforming principle was DNA. The document also discusses how experiments on tobacco mosaic virus provided evidence that RNA can act as the genetic material for some viruses.
RNA AS GENETIC MATERIAL
RNA plays important roles in coding, decoding, regulating, and expressing genes. Some viruses use RNA as their genetic material, including those that cause diseases like SARS, influenza, hepatitis C, and measles. Tobacco mosaic virus (TMV) was the first virus crystallized and shown through experiments to have RNA, not DNA, as its genetic material. When purified TMV RNA was inoculated into healthy tobacco plants, it caused lesions, demonstrating that the RNA alone carried the genetic information to cause infection.
Reverse Transcription of RNA
Reverse transcription of RNA is a process whereby RNA, typically messenger RNA is converted into complimentary DNA. The process was discovered by Howard Temin and John Baltimore when they observed that certain RNA viruses could revert to DNA. This was an important discovery that led to the discovery of enzymes classified as reverse transcriptases. Today Reverse Transcription is routinely applied in molecular biology laboratories to obtain the stable cDNA version of RNA for downstream analysis.
RNA SPLICING
RNA splicing is a process where introns are removed from precursor messenger RNA (pre-mRNA) and exons are joined together to produce mature mRNA. It occurs in the nucleus and is essential for eukaryotes to produce proteins. The spliceosome, a large complex of RNA and proteins, facilitates two transesterification reactions that remove introns and ligate exons. RNA splicing generates protein diversity through alternative splicing and is important for cellular functions and disease processes.
Charging of tRNA, Aminoacyl tRNA Synthetases
CBCS 4TH SEM ,
CHARGING, STRUCTURE AND FUNCTION OF tRNA,
AMINOACYL RNA SYNTHETASE(ASR) PROOFREADING AND EDITING
https://www.youtube.com/watch?v=YzOVMWYLiCE
Plasmid
This document provides an overview of plasmids. It defines plasmids as small, circular, extrachromosomal DNA molecules that can replicate independently in bacteria. Plasmids contain genes that provide benefits to bacteria like antibiotic resistance. They are transferred between bacteria through processes like transformation, transduction, and conjugation. Plasmids are classified based on their functions and are important tools in biotechnology as they allow cloning, protein production, and other applications.
Griffith experiment
details of all the steps and conclusion done by Griffith in his experiment and further research by Avery, Macleod, McCarty on the same.
Transformation in bacteria
transformation in bacteria is a classical example of horizontal gene transfer which leads to enhanced survivability and also introduction of variations that may lead to evolution
Bacterial genomic organization
A detail comparison between the genomic organization between prokaryotic genome and eukaryotic genome.
Transcription in Eukaryotes
Transcription in eukaryotes is carried out by three RNA polymerases that synthesize different RNA molecules. RNA polymerase II initiates transcription through assembly of general transcription factors and a mediator complex at DNA promoter sequences. Initiation is followed by elongation and termination steps. Additional factors are required at each step to facilitate efficient transcription. The resulting RNA transcripts undergo processing including capping, polyadenylation, and export from the nucleus. Prokaryotic transcription differs in that it occurs in the cytoplasm and involves a single RNA polymerase, while eukaryotic transcription takes place in the nucleus and requires multiple RNA polymerases and transcription factors.
Conjugation: Discovery, F+, F- and Hfr conjugation, F- genetic crosses
This document summarizes the discovery and mechanisms of bacterial conjugation. Joshua Lederberg and Edward Tatum discovered conjugation in 1946 while experimenting with E. coli strains. They found that when two auxotrophic strains were mixed on minimal media, prototrophs grew, indicating genetic transfer. Bernard Davis provided evidence for direct cell-to-cell contact in 1950 using a filter to separate strains. Conjugation involves an F plasmid transferring via pili from an F+ donor cell to an F- recipient. This can involve the whole chromosome in Hfr cells. The mechanisms of F+, F-, and Hfr conjugation and their genetic crosses are then described.
Transformation in bacteria
Genetic transformation is the incorporation of naked DNA from the extracellular environment into bacterial cells. There are two types of transformation: natural transformation which occurs naturally in some bacteria, and artificial transformation which is done through chemical, physical, or enzymatic treatment in the laboratory. The basic procedure of transformation involves isolating naked donor DNA, mixing it with competent recipient bacterial cells, and allowing the donor DNA to enter the recipient cells and recombine with the recipient genome.
Transcription in prokaryotes and eukaryotes
Transcription is the process of synthesizing RNA from DNA and involves four main stages - initiation, elongation, termination, and post-transcription processing. It occurs differently in prokaryotes and eukaryotes. In prokaryotes, transcription and translation are coupled and occur in the cytoplasm, while in eukaryotes transcription occurs separately in the nucleus. The document provides details on the mechanisms and factors involved in each stage of transcription for both prokaryotes and eukaryotes.
Transcription in prokaryotes
transcription process synthesized ssRNA in prokaryotes, RNA polymerase and promoter of prokaryotes and eukaryotes
RNA PROCESSING
RNA splicing, in molecular biology, is a form of RNA processing in which a newly made precursor messenger RNA transcript is transformed into a mature messenger RNA. During splicing, introns are removed and exons are joined together.
Transposition
transposable element is called transposons.it"s also known as jupping gene . it involves replicative and non replicative mechanism.
Transcription in eukaryotes
transcription process in eukaryotes their factors RNA polymerase enzyme an intiation elongation termination process
Dna replication in prokaroytes and in eukaryotes
1. DNA replication is the process where parental DNA is used as a template to produce identical copies of DNA or daughter DNA. It ensures faithful transmission of genetic material to offspring.
2. Replication starts at specific origins of replication and involves initiation, elongation, and termination phases. Enzymes involved include DNA polymerases, helicases, primases, ligases and more.
3. Eukaryotic replication is more complex, with multiple polymerases and regulated initiation. Telomerase is required for end-replication and chromosome integrity.
4. DNA repair mechanisms include base excision, nucleotide excision, mismatch and double-strand break repair to fix errors and damage via pathways like non-homologous
Lamda phage
Lambda phage is a bacteriophage that infects E. coli bacteria. It has two life cycles: a lytic cycle and a lysogenic cycle. In the lytic cycle, the phage genome is transferred into the bacterial cell where it replicates and causes the bacterial cell to burst, releasing new phage particles. In the lysogenic cycle, the phage genome integrates into the bacterial chromosome and replicates with the host DNA without killing the cell. The phage can switch between these two cycles depending on environmental conditions inside the infected bacterial cell.
Phi x 174 phage.
This presentation is about the Phi X 174 phage which include detail information of morphology, life cycle and genome organization of phi X 174 phage.
DNA as genetic material
1) Griffith discovered a "transforming principle" that allowed non-virulent bacteria to become virulent after exposure to heat-killed virulent bacteria.
2) Avery, MacLeod, and McCarty determined that the transforming principle was DNA through experiments treating components with DNAses, RNAses, and proteases.
3) Hershey and Chase provided definitive evidence that DNA is the genetic material through experiments using bacteriophages containing radioactive DNA or protein to infect bacteria, showing that only DNA was transferred.
homologus recombination
This document summarizes homologous recombination in eukaryotes and bacteria. In eukaryotes, homologous recombination repairs double-strand DNA breaks through either the double-strand break repair (DSBR) pathway or synthesis-dependent strand annealing (SDSA) pathway. The DSBR pathway forms double Holliday junctions that are resolved to result in crossover or non-crossover products. In bacteria, the RecBCD pathway repairs double-strand breaks and the RecF pathway repairs single-strand gaps. Both pathways involve strand invasion and branch migration to facilitate homologous recombination.
Enzymes of DNA replication
Enzymes of DNA replicationMarudhar Kesari Jain College for Women Vaniyambadi - 635 751, Tamil Nadu, INDIA.
DNA replication is the process where one original DNA molecule is copied to produce two identical DNA molecules. It occurs through semiconservative replication where each strand of the original DNA serves as a template for the production of the complementary strand. The replication fork forms during DNA replication through the unwinding of the DNA double helix by helicases. It has two branching prongs that serve as templates for the leading and lagging strands which are synthesized by DNA polymerase.Dna supercoiling and role of topoisomerases
supercoiling is one of the important process to condenses the huge amount of DNA to fit inside the histone and its also plays a role during the replication ,transcription etc..,these activities is carried out by an enzyme called topoisomerases.
DNA replication in E.coli
DNA replication in E.coli
Introduction
Definition
E.coli as a study model
Basic step of DNA replication
Cromatin Remodeling
1. Chromatin remodeling is the process by which chromatin structure is dynamically modified to allow access of DNA for processes like transcription.
2. There are two main types of chromatin remodeling - covalent histone modification and ATP-dependent chromatin remodeling complexes.
3. ATP-dependent complexes use energy from ATP hydrolysis to move, eject, or restructure nucleosomes, allowing access to DNA.
4. Examples of chromatin remodeling complexes include SWI/SNF, ISWI, CHD, and INO80 families, which have different activities like nucleosome sliding or histone variant exchange.
Nucleic acid carries genetic material
Nucleic acid carries genetic material (Griffith’s Hershey & Chase Experiment, Avery- Macleod-McCarty Experiment, Hershey- Chase Experiment and Fraenkel-Conrat’s Experiment)
Dna an overview
This document provides an overview of DNA and genetics. It discusses how DNA was established as the genetic material through experiments in the 1940s-1950s, including Griffith's transformation experiments, Avery et al.'s work demonstrating the transforming principle was DNA, and Hershey and Chase's experiments with bacterial viruses. It also summarizes the discovery of the DNA double helix structure by Watson and Crick in 1953, based on Chargaff's rules and X-ray crystallography data. The key properties of DNA structure, including specific base pairing and semiconservative replication, are briefly outlined.
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Griffith experiment
details of all the steps and conclusion done by Griffith in his experiment and further research by Avery, Macleod, McCarty on the same.
Transformation in bacteria
transformation in bacteria is a classical example of horizontal gene transfer which leads to enhanced survivability and also introduction of variations that may lead to evolution
Bacterial genomic organization
A detail comparison between the genomic organization between prokaryotic genome and eukaryotic genome.
Transcription in Eukaryotes
Transcription in eukaryotes is carried out by three RNA polymerases that synthesize different RNA molecules. RNA polymerase II initiates transcription through assembly of general transcription factors and a mediator complex at DNA promoter sequences. Initiation is followed by elongation and termination steps. Additional factors are required at each step to facilitate efficient transcription. The resulting RNA transcripts undergo processing including capping, polyadenylation, and export from the nucleus. Prokaryotic transcription differs in that it occurs in the cytoplasm and involves a single RNA polymerase, while eukaryotic transcription takes place in the nucleus and requires multiple RNA polymerases and transcription factors.
Conjugation: Discovery, F+, F- and Hfr conjugation, F- genetic crosses
This document summarizes the discovery and mechanisms of bacterial conjugation. Joshua Lederberg and Edward Tatum discovered conjugation in 1946 while experimenting with E. coli strains. They found that when two auxotrophic strains were mixed on minimal media, prototrophs grew, indicating genetic transfer. Bernard Davis provided evidence for direct cell-to-cell contact in 1950 using a filter to separate strains. Conjugation involves an F plasmid transferring via pili from an F+ donor cell to an F- recipient. This can involve the whole chromosome in Hfr cells. The mechanisms of F+, F-, and Hfr conjugation and their genetic crosses are then described.
Transformation in bacteria
Genetic transformation is the incorporation of naked DNA from the extracellular environment into bacterial cells. There are two types of transformation: natural transformation which occurs naturally in some bacteria, and artificial transformation which is done through chemical, physical, or enzymatic treatment in the laboratory. The basic procedure of transformation involves isolating naked donor DNA, mixing it with competent recipient bacterial cells, and allowing the donor DNA to enter the recipient cells and recombine with the recipient genome.
Transcription in prokaryotes and eukaryotes
Transcription is the process of synthesizing RNA from DNA and involves four main stages - initiation, elongation, termination, and post-transcription processing. It occurs differently in prokaryotes and eukaryotes. In prokaryotes, transcription and translation are coupled and occur in the cytoplasm, while in eukaryotes transcription occurs separately in the nucleus. The document provides details on the mechanisms and factors involved in each stage of transcription for both prokaryotes and eukaryotes.
Transcription in prokaryotes
transcription process synthesized ssRNA in prokaryotes, RNA polymerase and promoter of prokaryotes and eukaryotes
RNA PROCESSING
RNA splicing, in molecular biology, is a form of RNA processing in which a newly made precursor messenger RNA transcript is transformed into a mature messenger RNA. During splicing, introns are removed and exons are joined together.
Transposition
transposable element is called transposons.it"s also known as jupping gene . it involves replicative and non replicative mechanism.
Transcription in eukaryotes
transcription process in eukaryotes their factors RNA polymerase enzyme an intiation elongation termination process
Dna replication in prokaroytes and in eukaryotes
1. DNA replication is the process where parental DNA is used as a template to produce identical copies of DNA or daughter DNA. It ensures faithful transmission of genetic material to offspring.
2. Replication starts at specific origins of replication and involves initiation, elongation, and termination phases. Enzymes involved include DNA polymerases, helicases, primases, ligases and more.
3. Eukaryotic replication is more complex, with multiple polymerases and regulated initiation. Telomerase is required for end-replication and chromosome integrity.
4. DNA repair mechanisms include base excision, nucleotide excision, mismatch and double-strand break repair to fix errors and damage via pathways like non-homologous
Lamda phage
Lambda phage is a bacteriophage that infects E. coli bacteria. It has two life cycles: a lytic cycle and a lysogenic cycle. In the lytic cycle, the phage genome is transferred into the bacterial cell where it replicates and causes the bacterial cell to burst, releasing new phage particles. In the lysogenic cycle, the phage genome integrates into the bacterial chromosome and replicates with the host DNA without killing the cell. The phage can switch between these two cycles depending on environmental conditions inside the infected bacterial cell.
Phi x 174 phage.
This presentation is about the Phi X 174 phage which include detail information of morphology, life cycle and genome organization of phi X 174 phage.
DNA as genetic material
1) Griffith discovered a "transforming principle" that allowed non-virulent bacteria to become virulent after exposure to heat-killed virulent bacteria.
2) Avery, MacLeod, and McCarty determined that the transforming principle was DNA through experiments treating components with DNAses, RNAses, and proteases.
3) Hershey and Chase provided definitive evidence that DNA is the genetic material through experiments using bacteriophages containing radioactive DNA or protein to infect bacteria, showing that only DNA was transferred.
homologus recombination
This document summarizes homologous recombination in eukaryotes and bacteria. In eukaryotes, homologous recombination repairs double-strand DNA breaks through either the double-strand break repair (DSBR) pathway or synthesis-dependent strand annealing (SDSA) pathway. The DSBR pathway forms double Holliday junctions that are resolved to result in crossover or non-crossover products. In bacteria, the RecBCD pathway repairs double-strand breaks and the RecF pathway repairs single-strand gaps. Both pathways involve strand invasion and branch migration to facilitate homologous recombination.
Enzymes of DNA replication
Enzymes of DNA replicationMarudhar Kesari Jain College for Women Vaniyambadi - 635 751, Tamil Nadu, INDIA.
DNA replication is the process where one original DNA molecule is copied to produce two identical DNA molecules. It occurs through semiconservative replication where each strand of the original DNA serves as a template for the production of the complementary strand. The replication fork forms during DNA replication through the unwinding of the DNA double helix by helicases. It has two branching prongs that serve as templates for the leading and lagging strands which are synthesized by DNA polymerase.Dna supercoiling and role of topoisomerases
supercoiling is one of the important process to condenses the huge amount of DNA to fit inside the histone and its also plays a role during the replication ,transcription etc..,these activities is carried out by an enzyme called topoisomerases.
DNA replication in E.coli
DNA replication in E.coli
Introduction
Definition
E.coli as a study model
Basic step of DNA replication
Cromatin Remodeling
1. Chromatin remodeling is the process by which chromatin structure is dynamically modified to allow access of DNA for processes like transcription.
2. There are two main types of chromatin remodeling - covalent histone modification and ATP-dependent chromatin remodeling complexes.
3. ATP-dependent complexes use energy from ATP hydrolysis to move, eject, or restructure nucleosomes, allowing access to DNA.
4. Examples of chromatin remodeling complexes include SWI/SNF, ISWI, CHD, and INO80 families, which have different activities like nucleosome sliding or histone variant exchange.
What's hot (20)
Conjugation: Discovery, F+, F- and Hfr conjugation, F- genetic crosses
Conjugation: Discovery, F+, F- and Hfr conjugation, F- genetic crosses
Similar to Nucleic acid carries genetic material part-1
Nucleic acid carries genetic material
Nucleic acid carries genetic material (Griffith’s Hershey & Chase Experiment, Avery- Macleod-McCarty Experiment, Hershey- Chase Experiment and Fraenkel-Conrat’s Experiment)
Dna an overview
This document provides an overview of DNA and genetics. It discusses how DNA was established as the genetic material through experiments in the 1940s-1950s, including Griffith's transformation experiments, Avery et al.'s work demonstrating the transforming principle was DNA, and Hershey and Chase's experiments with bacterial viruses. It also summarizes the discovery of the DNA double helix structure by Watson and Crick in 1953, based on Chargaff's rules and X-ray crystallography data. The key properties of DNA structure, including specific base pairing and semiconservative replication, are briefly outlined.
Mol bio
1) The document provides an overview of DNA structure and function. It describes DNA as the genetic material that carries hereditary information from one generation to the next in the form of genes.
2) The key experiments that proved DNA is the genetic material are described, including Griffith's transformation experiment, Avery's work showing the transforming principle is DNA, and Hershey and Chase's experiment using radioactive labeling of DNA and proteins in bacteriophages.
3) Watson and Crick are credited with discovering the double helix structure of DNA in 1953 based on Chargaff's rules of base pairing and X-ray crystallography data. Their model explained DNA's ability to self-replicate semiconserv
DNA as genetic material
Frederick Griffith's experiments in 1928 showed that a transforming principle could pass from dead virulent pneumonia bacteria to live avirulent bacteria, making them deadly. Oswald Avery later purified this principle and through chemical and enzymatic tests determined it was DNA, not protein as previously believed. In 1952, Hershey and Chase used radioactive labeling to track the entry of DNA and proteins from bacteriophages into infected bacteria. They found that only the labeled DNA entered the bacterial cells, providing definitive evidence that DNA is the genetic material.
DNA : genetic material Experiments
Frederick Griffith conducted experiments in 1928 using two strains of Streptococcus pneumoniae bacteria - R strain and S strain. The R strain was non-virulent while the S strain was virulent. Griffith found that when he injected a mixture of heat-killed S bacteria and live R bacteria into mice, the mice became sick, showing that something from the S bacteria had transformed the R bacteria. Later experiments by Avery, McCarty, and MacLeod in 1944 identified this transforming substance as DNA. Further experiments by Hershey and Chase in the 1950s using bacteriophage viruses provided more evidence that DNA, not protein, was the genetic material being transferred from viruses to bacteria to cause infection.
Frederick Griffith's Experiment.ppt GENx
Frederick Griffith conducted an experiment in 1928 demonstrating that genetic information could be transferred between bacteria strains. He found that mice survived when injected with a non-virulent strain or heat-killed virulent strain, but died when injected with a mixture of both. This showed that the non-virulent strain acquired some "transforming principle" making it virulent. Later experiments by Avery, MacLeod and McCarty purified components from the bacteria and found that only DNA was responsible for the transformation, identifying DNA as the genetic material.
Gene transfer mechanisms
- Griffith's experiment showed that a non-pathogenic strain of bacteria could be transformed into a pathogenic strain after exposure to heat-killed pathogenic bacteria. This indicated the presence of a "transforming principle" that could alter the bacteria's genetic properties.
- Later experiments by Avery, MacLeod and McCarty identified DNA as the molecule responsible for bacterial transformation. They showed that DNA is the genetic material that is able to transform one type of bacteria into another through uptake and incorporation of foreign DNA.
- Transformation, transduction, and conjugation are mechanisms by which prokaryotes can transfer genetic material between each other. Transformation involves taking up free DNA from the environment, while conjugation involves direct transfer of DNA through
DNA -Genetic Material
The document provides an overview of DNA structure and function. It discusses early experiments that established DNA as the genetic material, including Griffith's experiments showing transformation in bacteria and Avery, Macleod and McCarty's experiments proving that DNA is the transforming principle. It describes Chargaff's rules, Watson and Crick's proposal of the double helix model based on X-ray diffraction data, and semiconservative DNA replication demonstrated by Meselson and Stahl's experiment using nitrogen isotopes.
Transforming principle..
Frederick Griffith discovered the principle of transformation through experiments with Streptococcus pneumoniae bacteria. He found that heat-killed virulent S-strain bacteria could make non-virulent R-strain bacteria transform and become virulent. Later, Oswald Avery, Colin MacLeod and Maclyn McCarty discovered that DNA alone from S bacteria could transform R bacteria. Alfred Hershey and Martha Chase provided conclusive evidence that DNA, not protein, is the genetic material through experiments using bacteriophages infecting E. coli bacteria. They found that radioactive DNA, but not protein, passed from the bacteriophages into the bacterial cells.
genetransferinbacteria-kartik-141116071759-conversion-gate01.pdf
This document provides an overview of gene transfer in bacteria through three main methods: conjugation, transformation, and transduction. Conjugation involves the transfer of genetic material between bacteria via cell-to-cell contact through sex pili. Transformation refers to the uptake of naked DNA by competent bacterial cells. Transduction is the transfer of DNA from one bacterium to another via bacteriophage. Each method is described in 1-2 paragraphs detailing its history of discovery and basic mechanisms.
Gene transfer in bacteria
This document provides an overview of gene transfer in bacteria through three main methods: conjugation, transformation, and transduction. Conjugation involves the transfer of genetic material between bacteria via cell-to-cell contact through sex pili. Transformation refers to the uptake of naked DNA by competent bacterial cells. Transduction is the transfer of DNA from one bacterium to another via bacteriophage. Each method is described in 1-2 paragraphs detailing its history of discovery and basic mechanisms.
mechanism of gene transfer prokaryotes
This document discusses three mechanisms of gene transfer in prokaryotes: conjugation, transformation, and transduction. Conjugation involves the transfer of genetic material between bacteria via cell-to-cell contact through sex pili. Transformation refers to the uptake of naked DNA by competent bacterial cells. Transduction is the transfer of DNA from one bacterium to another via bacteriophages. The document provides historical context and methodological details for each of these gene transfer mechanisms.
DNA as genetic material
The document summarizes several key experiments that helped establish DNA as the genetic material:
- Griffith's experiment showed a "transforming principle" in dead bacteria could change live bacteria;
- Avery, McCarty and MacLeod purified and identified this principle as DNA;
- Hershey and Chase showed that DNA, not protein, was injected by viruses into infected bacteria;
- Fraenkel-Conrat's experiment proved that RNA could also act as genetic material.
Rosalind Franklin's X-ray crystallography work provided evidence of DNA's double-helix structure, though she did not receive full credit due to gender biases of the time.
molecular genetics
1. Griffith's experiments in 1928 showed that heat-killed type IIIS bacteria could transform live type IIR bacteria into the virulent type IIIS strain.
2. Avery, Macleod and McCarty repeated Griffith's experiments in 1944 using purified extracts and found that DNA is the transforming agent.
3. Hershey and Chase provided further evidence in 1952 using radioactive labeling to track the entry of bacteriophage components into infected bacteria, showing that DNA rather than protein enters bacterial cells during infection.
Animal transformation
This presentation consists of introduction of animal transformation as well as the methods and applications.
Introduction to Molecular Biology 1.pptx
Molecular biology is a branch of science concerning biological activity
in terms of molecular basis, including the interactions between DNA,
Cells are the basic unit of all living things. In terms of self-replication,
cells are the smallest life form, which have the ability for
reproduction.
RNA and proteins.
FAMOUS MOLECULAR BIOLOGY EXPERIMENTS
The document summarizes several key experiments that helped establish DNA as the genetic material:
1) Griffith's transforming principle experiment in 1928 demonstrated that something from heat-killed bacteria could transform live bacteria, indicating the presence of a "transforming principle."
2) Avery, McCarty, and MacLeod purified this principle in 1944 and showed that it was DNA through a series of tests.
3) Hershey and Chase's 1952 experiment using bacteriophage proved that the genetic material injected into bacteria was DNA, not protein.
4) Chargaff formulated his rules in 1950 showing equal concentrations of DNA bases adenine and thymine and guanine and cytosine.
5) Mesel
0. Experiments.pptx
Frederick Griffith conducted an experiment in 1928 involving two strains of Streptococcus pneumoniae bacteria - rough and smooth strains. When mice were injected with a mixture of live rough bacteria and heat-killed smooth bacteria, the mice became sick, and live smooth bacteria were found in their blood, showing that the rough bacteria had transformed into the virulent smooth strain. Later experiments by Avery, McCarty and MacLeod in 1944 identified DNA as the molecule responsible for this transformation. Hershey and Chase further confirmed in 1952 that DNA, not protein, was the genetic material through experiments involving radioactively labeled bacteriophages.
12.1 notes
1) Bacterial transformation experiments by Griffith and Avery's team showed that DNA is the genetic material that can be transferred between bacteria to alter traits like disease-causing ability.
2) Hershey and Chase's experiments with bacteriophages demonstrated that viral DNA, not the protein coat, enters bacterial cells to transmit the viral genes.
3) DNA functions to store, copy, and transmit genetic information from parent to daughter cells and between generations through its molecular structure and role in heredity.
Modern genetics
This document provides an overview of modern genetics. It begins by defining genetics as the study of heredity and genes. It describes Gregor Mendel's foundational work in genetics and how his work led to the modern understanding of genes and inheritance being controlled by DNA. Key experiments that established DNA as the genetic material, such as Griffith's transformation experiment and Hershey and Chase's experiment, are summarized. The central dogma of biology involving DNA replication, transcription of DNA to mRNA, and translation of mRNA to proteins is explained at a high level. Concepts covered include DNA and RNA structure, mutation, genetic engineering techniques like recombinant DNA, and applications to medical genetics research.
Similar to Nucleic acid carries genetic material part-1 (20)
genetransferinbacteria-kartik-141116071759-conversion-gate01.pdf
genetransferinbacteria-kartik-141116071759-conversion-gate01.pdf
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The document summarizes the Ramachandran plot, which is a plot of the phi and psi dihedral angles of amino acid residues in protein structures. It was originally developed in 1963 to show possible conformations of phi and psi angles for amino acid residues and the empirical distribution of these angles observed in protein structures. The plot takes advantage of the circular nature of dihedral angles, with edges wrapping from right to left and bottom to top. It can be used to determine amino acid preferences and how the presence or absence of groups like a methylene group at C-beta affect the angles.
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The document discusses the mechanism of ascent of sap in plants. It describes several experiments that were conducted to study this process, including the eosin experiment and ringing experiment. It also discusses and rejects several proposed theories for the ascent of sap, such as the root pressure theory, vital theories, and imbibition theory. The document concludes that the transpiration pull and cohesive properties of water theory provides the most convincing explanation for how water moves upwards in plants. According to this theory, transpiration from leaves creates tension in the xylem vessels that pulls water upwards through the plant.
Transport in plant (Plant physiology)
Transport in plants occurs over long distances through the vascular system or within cells. Materials move in and out of cells by diffusion, facilitated diffusion, or active transport. Diffusion is a passive, slow movement along a concentration gradient without energy expenditure. Facilitated diffusion uses helper proteins like porins and aquaporins to selectively transport hydrophilic substances without expending energy. Active transport moves substances against a concentration gradient faster than passive transport by utilizing ATP as an energy source.
Methods of illustrating evolutionary relationship
Phylogenetic trees illustrate evolutionary relationships between individuals or species. There are several methods to construct phylogenetic trees, including distance-matrix methods like Neighbor Joining and UPGMA, as well as Maximum Parsimony, Maximum Likelihood, and Bayesian Inference. These methods analyze genetic distances and sequences to determine which individuals or species share a common evolutionary ancestor based on their similarities and differences. Accurately depicting evolutionary relationships is important for fields like medicine to discover new treatments from closely-related species.
Co-evolution of angiosperms and animals
The document discusses several examples of coevolution between species:
1. Predator-prey relationships like between predators and their prey lead to an evolutionary arms race as each evolves adaptations to hunt or avoid being caught.
2. Herbivores and the plants they eat also coevolve, as seen with lodgepole pine cones adapting differently depending on whether squirrels or crossbills are present.
3. Acacia ants and acacia plants have a mutualistic relationship where the ants protect the plants and the plants provide food and shelter for the ants.
4. Flowering plants and their pollinators like bees, birds and insects have coevolved mutual adaptations - flowers attract
Angiosperms
This document summarizes key aspects of angiosperms including their evolution, life cycle, and the field of systematic botany. It discusses how angiosperms evolved diversified forms and efficient reproduction mechanisms. Their life cycle involves an alternation between a dominant sporophyte generation and a reduced parasitic gametophyte generation. Systematic botany aims to classify and name all plant species based on their morphology and relationships, which is important for fields like agriculture, forestry, and ecology.
Operational taxonomic unit (OTUs)
An operational taxonomic unit (OTU) is a pragmatic definition used to group closely related organisms or unknown microbes based on DNA sequence similarity. OTUs cluster sequences of a marker gene, like 16S rRNA for prokaryotes, according to a similarity threshold chosen by the researcher, usually 97%. This operational definition allows the study and classification of microbes lacking traditional taxonomy and serves as a proxy for "species" when analyzing sequence datasets.
Numerical taxonomy
Numerical taxonomy refers to the application of mathematical and computational methods to analyze taxonomic data and evaluate the similarities between organisms. It involves assigning numerical values to characterize similarities between organisms based on many descriptive characters. The taxa are then organized based on their calculated affinities. Numerical taxonomy aims to provide more objective and data-driven classifications compared to traditional taxonomy.
Data mining
Cluster analysis is an unsupervised machine learning technique used to group similar objects together. It partitions data into clusters where objects within a cluster are as similar as possible to each other, and as dissimilar as possible to objects in other clusters. There are several clustering methods including partitioning, hierarchical, density-based, grid-based, and model-based. Clustering is widely used in applications such as market segmentation, document classification, and fraud detection.
Cladistic
Cladistics is a biological classification system that groups organisms based on shared traits and evolutionary relationships. It aims to trace ancestry back to common ancestors by constructing phylogenetic trees based on morphological and molecular data. Key terms in cladistics include plesiomorphy (ancestral traits), apomorphy (derived traits that define groups), and homoplasy (traits that evolved separately in different groups). Together, analysis of character states helps determine evolutionary relationships between taxa.
Functional aspects of ecosystem
This document discusses energy flow and nutrient cycling in ecosystems. It can be summarized as follows:
1. Energy from the sun enters ecosystems through photosynthesis, where it is converted to chemical energy in plants. This energy then passes through food chains to consumers, with some energy lost as heat at each trophic level.
2. Nutrients cycle through ecosystems, moving between biotic and abiotic components. Major nutrient cycles include carbon, nitrogen, and phosphorus, which cycle globally or locally between organisms, soils, water, and the atmosphere.
3. Energy and matter transfer with low efficiencies between trophic levels, with around 10% of energy typically transferred between each level according to Lindeman's law
Cot curve
Cot value and Cot Curve analysis is a technique for measuring DNA complexity based on renaturation kinetics. DNA is denatured and allowed to reanneal, with larger DNA taking longer. Cot value accounts for DNA concentration, time, and buffer effects, representing repetitive sequences - lower Cot means more repeats. Examples show bacteria have nearly all single-copy DNA, while mouse has varying proportions of single-copy, middle repetitive, and highly repetitive sequences. Cot curve analysis provides information on genome size, complexity, and proportions of sequence types.
Semiconservative DNA replication
DNA replicates through a process called semiconservative replication, where each parental DNA strand serves as a template to produce two identical daughter double helices, each with one parental and one new strand. The Meselson-Stahl experiment demonstrated this by growing E. coli in heavy nitrogen, then transferring to light nitrogen and analyzing DNA density over generations, finding bands matching semiconservative replication but not other models like conservative or dispersive replication.
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 of DNA
DNA replication is the process by which a cell makes an identical copy of its DNA. It begins at specific locations in the genome called origins of replication. Enzymes such as helicase unwind and separate the double helix, while DNA polymerase adds complementary nucleotides to each strand to synthesize new daughter strands. The two resulting DNA molecules are identical to the original. Replication occurs through three coordinated steps - initiation, elongation, and termination. Initiation involves binding of proteins to origins of replication to form complexes. Elongation is catalyzed by DNA polymerase adding nucleotides to growing strands. There are two mechanisms for elongation - continuous synthesis of the leading strand and discontinuous synthesis of the lagging strand in fragments called Okazaki fragments.
Semiconservative replication
DNA replicates through a process called semiconservative replication, where each parental DNA strand serves as a template to produce two identical daughter double helices, each with one parental and one new strand. The Meselson-Stahl experiment demonstrated this by growing E. coli in heavy nitrogen, then transferring to light nitrogen and analyzing DNA density over generations, finding bands matching semiconservative replication.
Telomere replication
Telomeres are repetitive non-coding sequences at the ends of chromosomes that protect genes from being deleted during DNA replication. In humans, the telomere sequence is TTAGGG repeated 100 to 1000 times. With each cell division, some telomeric sequences are lost but this does not initially harm the cell. However, telomeres cannot be replicated indefinitely and will eventually be completely lost without a mechanism to maintain their length. The enzyme telomerase was discovered to attach to chromosome ends and uses its internal RNA template to add telomeric repeats to the 3' end of DNA strands, allowing chromosome ends to be fully replicated.
DNA replication
This document summarizes DNA replication in eukaryotic cells. It begins with an overview of DNA replication, including that it occurs during S phase and produces two identical DNA molecules from one original. It then describes the process of initiation, elongation, and termination of DNA replication. Initiation involves unwinding of DNA and formation of replication forks. Elongation involves continuous synthesis of the leading strand and discontinuous synthesis of the Okazaki fragments on the lagging strand. The document discusses several models of replication, including rolling circle replication, theta replication in prokaryotes, and replication of linear and telomeric DNA. It highlights key aspects like semiconservative replication being shown by Meselson-Stahl experiments. In
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Chapter 2
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Nucleic acid carries genetic material part-1
- 1. Nucleic Acid- Carries genetic material Part-1 Griffith’s Hershey & Chase & Avery- Macleod-McCarty Experiment Dr. Emasushan Minj Assistant Professor Department of Botany
- 2. What is genetic material? Genetic material, also known as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), plays a fundamental role in the composition of living organisms and responsible for controlling hereditary characters.
- 3. Griffith’s Hershey & Chase experiment • The process of transformation was first discovered by Frederick Griffith in 1928. • This was called as Griffith’s effect. • Transformation is the mode of exchange or transfer of genetic information (recombination) from one strain of bacterium to another strain of bacterium without involving any direct contact between them. • Griffith performed transformation experiments with two different strains of the bacterium Diplococcus pneumoniae.
- 4. • Diplococcus pneumonia is now named as Streptococcus Pneumoniae. • There are two types of strains i.e. Virulent and Avirulent strains. • Virulent strains are those which cause pneumonia in certain vertebrates (Such as mice and human) and avirulent strains are those which do not cause pneumonia. • The difference in virulence is due to bacterium polysaccharide capsule is not easily engulfed. Hence, they are able to cause pneumonia.
- 5. • Non-capsulated bacteria are readily engulfed and destroyed by phagocytic cells. • On agar culture medium encapsulated strains forms smooth colonies and non-encapsulated strains forms rough colonies. • They have different serotypes- i.e. IS, IIS & IIS or IR, IIR & IIIR. • IIR &IIIS was used in the experiment serotype was identified by immunological techniques.
- 6. • Griffith injected different strains of bacteria in mice. • The IIIS strain killed the mice and IIR did not. • Heat killed IIIS strain did not cause pneumonia • Further heat killed IIIS and live IIR together injected to the mice, which kills the mice. • Griffith concluded that heat killed IIIS is responsible for the conversion of IIR in Virulent strain. This phenomenon is known as Transformation. Genetic information is getting passed from dead IIIS to IIR cells by transforming principle.
- 7. Avery- Macleod-McCarty experiment • This experiment is also known as Transformation in Pneumococcus. • It is the direct evidence showing that the genetic material is DNA rather than protein or RNA. • In 1944, Oswald Avery, Colin Macleod and Maclyn McCarty revisited Griffith’s experiment and concluded that the transforming material was pure DNA not protein or RNA. • They found that DNA extracted from virulent strain of the bacterium Streptococcus pneumoniae, genetically transformed an avirulent strain of this organism into a virulent form.
- 8. *To demonstrate that contamination molecules in the DNA extract were not responsible for transformation, theDNA extract from S cells was treated with RNase, DNase and protease and then mixed with with R cells.
- 9. Experiment:- • IIR- strain being Non-virulent and non-capsulated shows no transformation. • When IIR-strain and IIIS DNA extract was injected into mice resultant transformation took place. • Further IIR-strain, IIIS DNA extract and DNase was injected there was no transformation because of DNA was destroyed by DNase. • Further experiment was continued with another combination i.e. IIR-strain, IIIS DNA extract and RNase was injected. Resultant transformation took place. Here RNA was destroyed by RNase. • Another combination of IIR-strain, IIIS DNA extract with protease was injected and showed transformation. Here protease destroyed the protein.
- 10. • This experiment was concluded proving that DNA is responsible for genetic information transfer and transformation. Because when DNase was used there was no transformation and transformation occur when RNase and protease were used as they contain DNA. Hence it was proved that genetic information carried by DNA rather than protein or RNA.
- 11. Thank you