Chromosomes contain DNA and proteins. In eukaryotes, chromosomes are located in the nucleus and must be highly compacted to fit by binding proteins to form chromatin. Chromatin is compacted in a hierarchical manner through nucleosomes, the 30nm fiber, and looping domains which further shortens the DNA about 50-fold to fit in the nucleus. Each chromosome occupies a distinct territory.
Facts about DNA
Eukaryotic chromosomes
Chemical composition of eukaryotic chromosomes
Histones
Non-histone chromosomal protein
Scaffold proteins
Folded fibre model
Nucleosome model
H1 proteins
Histone modification
Chromatosome
Higher order of chromatin structure
Mechanism of DNA packaging
Conclusion
This document describes the process of DNA replication in eukaryotes. It occurs in S phase of the cell cycle and involves three main stages: initiation, formation of the initiation complex, and elongation. Initiation requires the assembly of pre-replication complexes containing ORC, Cdc6, Cdt1 and MCM proteins. In S phase, Cdc45 and GINS are recruited to form the initiation complex. Elongation proceeds bidirectionally from replication forks, with leading strand synthesis continuous and lagging strand discontinuous via Okazaki fragments. Replication terminates at telomeres.
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.
C VALUE, C VALUE PARADOX , COT CURVE ANALYSIS.pptxMurugaveni B
This document discusses the C-value, C-value paradox, and COT curve analysis. It defines the C-value as the total amount of DNA in a genome. It explains that the C-value paradox arose because early research assumed complexity increased with DNA amount, but some organisms like salamanders have more DNA than humans despite lower complexity. The document outlines the COT curve technique which analyzes renaturation kinetics to measure genome complexity based on repetitive sequences. It applies COT curve analysis to understand genome size, sequence complexity, and the proportion of single-copy versus repetitive DNA.
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.
Prokaryotic genomes are typically organized as single circular chromosomes that are condensed into a nucleoid region within the cell. DNA supercoiling, which involves the over- or under-winding of DNA strands, facilitates compaction of prokaryotic genomes and enables DNA metabolism. Topoisomerases regulate DNA supercoiling by introducing temporary breaks in DNA strands, allowing strands to pass through one another and relieve torsional stress that builds during processes like transcription and replication. The two major types of topoisomerase are types I and II, which introduce single-strand or double-strand breaks, respectively, in regulating supercoiling levels.
This Presentation will be helpful to undergraduate and postgraduate students of biology and biotechnology in understanding the significance of COT curves in determination of gene and genome complexity amoug various organisms
Facts about DNA
Eukaryotic chromosomes
Chemical composition of eukaryotic chromosomes
Histones
Non-histone chromosomal protein
Scaffold proteins
Folded fibre model
Nucleosome model
H1 proteins
Histone modification
Chromatosome
Higher order of chromatin structure
Mechanism of DNA packaging
Conclusion
This document describes the process of DNA replication in eukaryotes. It occurs in S phase of the cell cycle and involves three main stages: initiation, formation of the initiation complex, and elongation. Initiation requires the assembly of pre-replication complexes containing ORC, Cdc6, Cdt1 and MCM proteins. In S phase, Cdc45 and GINS are recruited to form the initiation complex. Elongation proceeds bidirectionally from replication forks, with leading strand synthesis continuous and lagging strand discontinuous via Okazaki fragments. Replication terminates at telomeres.
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.
C VALUE, C VALUE PARADOX , COT CURVE ANALYSIS.pptxMurugaveni B
This document discusses the C-value, C-value paradox, and COT curve analysis. It defines the C-value as the total amount of DNA in a genome. It explains that the C-value paradox arose because early research assumed complexity increased with DNA amount, but some organisms like salamanders have more DNA than humans despite lower complexity. The document outlines the COT curve technique which analyzes renaturation kinetics to measure genome complexity based on repetitive sequences. It applies COT curve analysis to understand genome size, sequence complexity, and the proportion of single-copy versus repetitive DNA.
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.
Prokaryotic genomes are typically organized as single circular chromosomes that are condensed into a nucleoid region within the cell. DNA supercoiling, which involves the over- or under-winding of DNA strands, facilitates compaction of prokaryotic genomes and enables DNA metabolism. Topoisomerases regulate DNA supercoiling by introducing temporary breaks in DNA strands, allowing strands to pass through one another and relieve torsional stress that builds during processes like transcription and replication. The two major types of topoisomerase are types I and II, which introduce single-strand or double-strand breaks, respectively, in regulating supercoiling levels.
This Presentation will be helpful to undergraduate and postgraduate students of biology and biotechnology in understanding the significance of COT curves in determination of gene and genome complexity amoug various organisms
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.
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
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.
DNA replication in prokaryotes begins with the unwinding of DNA at the origin of replication by enzymes like DnaA and DnaB helicase. This produces two replication forks that move in opposite directions. The leading strand is replicated continuously while the lagging strand is replicated discontinuously in short segments called Okazaki fragments. DNA polymerase III is the main enzyme that synthesizes new DNA. Replication terminates at the terminus region when the DnaB helicase is stopped by protein Tus bound to Ter sequences.
This document discusses the structures and functions of heterochromatin and euchromatin. Heterochromatin is tightly packed and transcriptionally inactive, found near centromeres and telomeres. Euchromatin is loosely packed and contains most actively transcribed genes. The basic unit of DNA packing is the nucleosome, which involves DNA wound around histone proteins. Heterochromatin and euchromatin differ in their genetic activity, location within chromosomes, and condensation levels during interphase.
This document provides lecture notes on DNA replication, damage, and repair. It discusses the process of DNA replication including the three main steps of initiation, elongation, and termination. Details are given on replication in prokaryotes and eukaryotes. The document also covers types of DNA damage including physical, chemical, and biological mutagens. Finally, various DNA repair mechanisms are summarized such as photoreactivation, excision repair, and SOS repair.
Dna supercoiling and role of topoisomerasesYashwanth B S
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 repair mechanisms in prokaryotes involve direct repair, excision repair, and mismatch repair. Direct repair converts damaged nucleotides directly back to their original structure using enzymes like photolyase. Excision repair removes damaged sections of DNA through base excision repair which removes single damaged bases using glycosylases and AP endonucleases, or nucleotide excision repair which removes short oligonucleotides. Mismatch repair recognizes and fixes errors made during DNA replication by distinguishing the parental DNA strands and excising the newly synthesized strand containing mistakes.
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.
Post-transcriptional modifications are important processes that convert primary transcript RNA into mature RNA. These modifications include 5' capping, 3' polyadenylation, and splicing of introns in eukaryotes. The modifications help make RNA molecules recognizable for translation and increase protein synthesis efficiency by removing non-coding regions. Different types of RNA undergo specific processing pathways involving nucleases, snoRNAs and other protein complexes.
DNA libraries allow for the storage and organization of genetic information, similar to how physical libraries store books. There are two main types of DNA libraries: genomic libraries, which are created from genomic DNA and contain entire genes with exons and introns, and cDNA libraries, which are created from mRNA and contain only exons. To create a genomic library, genomic DNA is isolated, fragmented, and inserted into cloning vectors within host bacteria. For cDNA libraries, mRNA is isolated, reverse transcribed into cDNA, which is then amplified and inserted into vectors. Both library types are screened to find clones containing desired DNA sequences.
Spontaneous mutations arise from errors in DNA replication and spontaneous DNA damage. Errors in replication can result in base substitutions if an incorrect base pairs with another. Spontaneous DNA damage includes depurination, in which bases are lost from DNA, and deamination of cytosine to uracil. Large deletions and duplications can also occur spontaneously. These replication errors and lesions generate the genetic variation that allows organisms to evolve in response to environmental changes. Spontaneous mutations are the ultimate source of natural genetic variation seen within populations and are responsible for certain human genetic diseases when they disrupt important genes.
RNA polymerase is an essential enzyme that copies DNA to produce different types of RNA in prokaryotes and eukaryotes. In prokaryotes, a single type of RNA polymerase synthesizes mRNA, tRNA, and rRNA. Transcription in prokaryotes involves initiation at promoter sequences, elongation as the RNA polymerase moves along DNA, and termination at specific sequences. Initiation requires the RNA polymerase binding to the promoter, unwinding the DNA, and beginning RNA synthesis. Elongation continues RNA synthesis as the DNA unwinds. Termination occurs at specific sequences like palindromes that allow RNA secondary structure formation and polymerase release.
RNA splicing is the process by which introns, or non-coding sequences, are removed from pre-messenger RNA (pre-mRNA) to produce mature mRNA that can be translated into protein. Most genes contain introns that are removed by a spliceosome, a complex of RNA and proteins, leaving just the coding exons to form mRNA. Alternative splicing allows one gene to encode multiple proteins by selecting different combinations of exons. Errors in splicing can cause diseases if they result in truncated or abnormal proteins.
Transcription in prokaryotes and eukaryotesMicrobiology
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.
The document discusses three models of DNA replication:
1) Asymmetric replication - the leading and lagging strands are replicated differently due to the 5' to 3' directionality of DNA polymerase. The leading strand replicates continuously while the lagging strand replicates discontinuously in short Okazaki fragments.
2) D-loop model - replication in mitochondria where one strand is displaced to form a D-loop and replicates first before the other strand.
3) Rolling circle model - used by plasmids and viruses where one strand is nicked and displaced to be used as a template, forming multiple copies linked together in a concatemer.
The document summarizes key aspects of nucleic acids. It describes that nucleic acids consist of sugars, nitrogenous bases, and phosphate groups. The four main nitrogenous bases are adenine, guanine, cytosine, and thymine in DNA or uracil in RNA. The document then discusses the primary, secondary, tertiary, and quaternary structure of nucleic acids. It also compares key differences between DNA and RNA as well as between mRNA and tRNA. Finally, it summarizes factors that contribute to the stability of the DNA double helix structure and differences between A, B, and Z forms of DNA.
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.
Genome organization in prokaryotes(molecular biology)IndrajaDoradla
1. In prokaryotes, the genome is located in an irregularly shaped region within the cell called the nucleoid, which is not surrounded by a membrane like the eukaryotic nucleus.
2. The prokaryotic genome is generally a circular piece of DNA that can exist in multiple copies and ranges in length but is at least a few million base pairs. It is packaged into the nucleoid through supercoiling facilitated by nucleoid-associated proteins.
3. DNA supercoiling allows for very long strands of DNA to be tightly packaged into a prokaryotic cell. This involves the introduction of plectonemic supercoils that twist the DNA into loops and wind it around nucle
DNA replication is the process by which a cell makes an identical copy of its DNA. It occurs in three main steps: initiation, elongation, and termination. Initiation begins at origins of replication and involves unwinding of the DNA double helix by helicases. During elongation, DNA polymerases add nucleotides to build new strands based on the existing DNA templates. Termination occurs when the replication forks meet at the end of the DNA molecule. DNA replication is semi-conservative, meaning each new DNA molecule contains one original and one new strand of DNA.
The document discusses genome structure and genomics. It defines key terms like genome, repetitive DNA, and defines the major classes of repetitive DNA, which constitute around 45% of the human genome. It discusses how DNA denaturation and renaturation kinetics can be used to determine genome complexity and GC content. Cot analysis allows characterization of sequence complexity based on repetitiveness. Eukaryotic genomes have lower gene density and finding genes is more challenging compared to prokaryotes due to introns and other factors.
Chromosomes contain DNA and proteins. In eukaryotes, chromosomes are located in the nucleus and must be highly compacted to fit by binding proteins to form chromatin. Chromatin is compacted in a hierarchical manner through interactions with histone proteins to form nucleosomes, which further compact to form the 30nm fiber and loop domains that attach to the nuclear matrix, compacting the DNA over 1000-fold to fit in the cell.
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.
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
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.
DNA replication in prokaryotes begins with the unwinding of DNA at the origin of replication by enzymes like DnaA and DnaB helicase. This produces two replication forks that move in opposite directions. The leading strand is replicated continuously while the lagging strand is replicated discontinuously in short segments called Okazaki fragments. DNA polymerase III is the main enzyme that synthesizes new DNA. Replication terminates at the terminus region when the DnaB helicase is stopped by protein Tus bound to Ter sequences.
This document discusses the structures and functions of heterochromatin and euchromatin. Heterochromatin is tightly packed and transcriptionally inactive, found near centromeres and telomeres. Euchromatin is loosely packed and contains most actively transcribed genes. The basic unit of DNA packing is the nucleosome, which involves DNA wound around histone proteins. Heterochromatin and euchromatin differ in their genetic activity, location within chromosomes, and condensation levels during interphase.
This document provides lecture notes on DNA replication, damage, and repair. It discusses the process of DNA replication including the three main steps of initiation, elongation, and termination. Details are given on replication in prokaryotes and eukaryotes. The document also covers types of DNA damage including physical, chemical, and biological mutagens. Finally, various DNA repair mechanisms are summarized such as photoreactivation, excision repair, and SOS repair.
Dna supercoiling and role of topoisomerasesYashwanth B S
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 repair mechanisms in prokaryotes involve direct repair, excision repair, and mismatch repair. Direct repair converts damaged nucleotides directly back to their original structure using enzymes like photolyase. Excision repair removes damaged sections of DNA through base excision repair which removes single damaged bases using glycosylases and AP endonucleases, or nucleotide excision repair which removes short oligonucleotides. Mismatch repair recognizes and fixes errors made during DNA replication by distinguishing the parental DNA strands and excising the newly synthesized strand containing mistakes.
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.
Post-transcriptional modifications are important processes that convert primary transcript RNA into mature RNA. These modifications include 5' capping, 3' polyadenylation, and splicing of introns in eukaryotes. The modifications help make RNA molecules recognizable for translation and increase protein synthesis efficiency by removing non-coding regions. Different types of RNA undergo specific processing pathways involving nucleases, snoRNAs and other protein complexes.
DNA libraries allow for the storage and organization of genetic information, similar to how physical libraries store books. There are two main types of DNA libraries: genomic libraries, which are created from genomic DNA and contain entire genes with exons and introns, and cDNA libraries, which are created from mRNA and contain only exons. To create a genomic library, genomic DNA is isolated, fragmented, and inserted into cloning vectors within host bacteria. For cDNA libraries, mRNA is isolated, reverse transcribed into cDNA, which is then amplified and inserted into vectors. Both library types are screened to find clones containing desired DNA sequences.
Spontaneous mutations arise from errors in DNA replication and spontaneous DNA damage. Errors in replication can result in base substitutions if an incorrect base pairs with another. Spontaneous DNA damage includes depurination, in which bases are lost from DNA, and deamination of cytosine to uracil. Large deletions and duplications can also occur spontaneously. These replication errors and lesions generate the genetic variation that allows organisms to evolve in response to environmental changes. Spontaneous mutations are the ultimate source of natural genetic variation seen within populations and are responsible for certain human genetic diseases when they disrupt important genes.
RNA polymerase is an essential enzyme that copies DNA to produce different types of RNA in prokaryotes and eukaryotes. In prokaryotes, a single type of RNA polymerase synthesizes mRNA, tRNA, and rRNA. Transcription in prokaryotes involves initiation at promoter sequences, elongation as the RNA polymerase moves along DNA, and termination at specific sequences. Initiation requires the RNA polymerase binding to the promoter, unwinding the DNA, and beginning RNA synthesis. Elongation continues RNA synthesis as the DNA unwinds. Termination occurs at specific sequences like palindromes that allow RNA secondary structure formation and polymerase release.
RNA splicing is the process by which introns, or non-coding sequences, are removed from pre-messenger RNA (pre-mRNA) to produce mature mRNA that can be translated into protein. Most genes contain introns that are removed by a spliceosome, a complex of RNA and proteins, leaving just the coding exons to form mRNA. Alternative splicing allows one gene to encode multiple proteins by selecting different combinations of exons. Errors in splicing can cause diseases if they result in truncated or abnormal proteins.
Transcription in prokaryotes and eukaryotesMicrobiology
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.
The document discusses three models of DNA replication:
1) Asymmetric replication - the leading and lagging strands are replicated differently due to the 5' to 3' directionality of DNA polymerase. The leading strand replicates continuously while the lagging strand replicates discontinuously in short Okazaki fragments.
2) D-loop model - replication in mitochondria where one strand is displaced to form a D-loop and replicates first before the other strand.
3) Rolling circle model - used by plasmids and viruses where one strand is nicked and displaced to be used as a template, forming multiple copies linked together in a concatemer.
The document summarizes key aspects of nucleic acids. It describes that nucleic acids consist of sugars, nitrogenous bases, and phosphate groups. The four main nitrogenous bases are adenine, guanine, cytosine, and thymine in DNA or uracil in RNA. The document then discusses the primary, secondary, tertiary, and quaternary structure of nucleic acids. It also compares key differences between DNA and RNA as well as between mRNA and tRNA. Finally, it summarizes factors that contribute to the stability of the DNA double helix structure and differences between A, B, and Z forms of DNA.
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.
Genome organization in prokaryotes(molecular biology)IndrajaDoradla
1. In prokaryotes, the genome is located in an irregularly shaped region within the cell called the nucleoid, which is not surrounded by a membrane like the eukaryotic nucleus.
2. The prokaryotic genome is generally a circular piece of DNA that can exist in multiple copies and ranges in length but is at least a few million base pairs. It is packaged into the nucleoid through supercoiling facilitated by nucleoid-associated proteins.
3. DNA supercoiling allows for very long strands of DNA to be tightly packaged into a prokaryotic cell. This involves the introduction of plectonemic supercoils that twist the DNA into loops and wind it around nucle
DNA replication is the process by which a cell makes an identical copy of its DNA. It occurs in three main steps: initiation, elongation, and termination. Initiation begins at origins of replication and involves unwinding of the DNA double helix by helicases. During elongation, DNA polymerases add nucleotides to build new strands based on the existing DNA templates. Termination occurs when the replication forks meet at the end of the DNA molecule. DNA replication is semi-conservative, meaning each new DNA molecule contains one original and one new strand of DNA.
The document discusses genome structure and genomics. It defines key terms like genome, repetitive DNA, and defines the major classes of repetitive DNA, which constitute around 45% of the human genome. It discusses how DNA denaturation and renaturation kinetics can be used to determine genome complexity and GC content. Cot analysis allows characterization of sequence complexity based on repetitiveness. Eukaryotic genomes have lower gene density and finding genes is more challenging compared to prokaryotes due to introns and other factors.
Chromosomes contain DNA and proteins. In eukaryotes, chromosomes are located in the nucleus and must be highly compacted to fit by binding proteins to form chromatin. Chromatin is compacted in a hierarchical manner through interactions with histone proteins to form nucleosomes, which further compact to form the 30nm fiber and loop domains that attach to the nuclear matrix, compacting the DNA over 1000-fold to fit in the cell.
- The document summarizes purine and pyrimidine nucleotide metabolism. It describes the biosynthesis and degradation pathways of purines and pyrimidines, and their regulation. Key enzymes and cofactors like tetrahydrofolate and PRPP are discussed.
- Inhibitors of nucleotide metabolism are important targets for cancer chemotherapy drugs. Drugs like methotrexate and fluorouracil inhibit key enzymes to selectively target rapidly dividing cancer cells.
- The metabolism of purines and pyrimidines provides the essential building blocks for nucleic acid synthesis and is tightly regulated through feedback inhibition at multiple steps in the pathways. Proper regulation is crucial as nucleotides are required for cell growth and proliferation.
The genetic code is a set of rules that translates DNA and RNA sequences into proteins. It was discovered that the genetic code uses three-letter "codons" to specify the 20 amino acids used to build proteins. Experiments in 1961 showed that poly-uracil RNA sequences coded for phenylalanine, poly-adenine for lysine, and poly-cytosine for proline. The genetic code is universal across all life with some minor variations, has start and stop codons, and its degeneracy makes it fault-tolerant against mutations.
Chromosomes contain an organism's genetic material and come in different structures depending on the organism. Bacteria typically have a single circular chromosome while eukaryotes have multiple linear chromosomes in the nucleus. Genetic material is highly compacted through various mechanisms to fit inside cells. In eukaryotes, DNA is wrapped around histone proteins to form nucleosomes, which further compact to form a 30nm fiber and loop domains that attach to a nuclear matrix, compacting the DNA over 1000-fold to fit in the nucleus.
1. Viral genomes contain DNA or RNA and are packaged into capsids through assembly processes. Bacterial chromosomes contain genes and other sequences compacted by looping and supercoiling.
2. Eukaryotic chromosomes vary greatly in size and contain genes and other sequences. Their DNA must be highly compacted to fit in the nucleus.
3. Eukaryotic DNA wraps around histone proteins to form nucleosomes, which further compact to form chromatin fibers and loop domains anchored to the nuclear matrix. Additional compaction occurs during cell division through condensin and cohesin proteins.
Chromosomes are structures that package and organize DNA and associated proteins. In eukaryotes, DNA is wrapped around histone proteins to form chromatin, which condenses into linear or circular chromosomes. Key features of eukaryotic chromosomes include centromeres, telomeres, and repetitive sequences. Chromosomes are compacted through DNA supercoiling and packaging into nucleosomes. The structure and packaging of chromosomes allows for efficient storage and regulation of the genetic material.
Chromosomes contain an organism's genetic material in the form of DNA. DNA sequences store the information needed to produce proteins, segregate chromosomes during cell division, replicate chromosomes, and compact chromosomes to fit inside cells. Viruses contain either DNA or RNA as their genetic material, which varies in size and structure between viruses. Bacterial chromosomes are typically circular DNA molecules containing several thousand genes, while eukaryotic chromosomes are linear and contain more DNA organized into nucleosomes and higher-order structures to fit inside the cell nucleus.
Dr.S.KARTHIKUMAR
Associate Professor
Department of Biotechnology
Kamaraj College of Engineering and Technology, K.Vellakulam-625701, TN, India
Email: skarthikumar@gmail.com
1. The document discusses the structure and organization of DNA and chromosomes in viruses, bacteria, and eukaryotes.
2. Key concepts covered include how DNA is packaged and compacted in these different organisms through association with proteins and coiling/supercoiling of the DNA double helix.
3. The nucleosome structure of eukaryotic chromatin is analyzed in detail through historical experiments using DNase I digestion, which supported the "beads on a string" model of DNA wrapped around histone protein cores.
The document provides an overview of microbial genetics and DNA manipulation techniques. It discusses [1] the central dogma of biology where DNA is transcribed into RNA and then translated into protein, [2] DNA structure including replication, transcription and translation, and [3] common genetic engineering techniques like using restriction enzymes to cut DNA and recombining DNA fragments into plasmids.
This document discusses DNA replication. It begins by explaining that DNA must be replicated accurately to maintain genetic information through cell divisions. It then discusses several key aspects of DNA replication:
1) DNA replication is semi-conservative, meaning the parental DNA strands separate and each acts as a template for a new complementary strand.
2) Replication occurs bidirectionally from replication origins. The leading strand replicates continuously while the lagging strand replicates discontinuously in fragments called Okazaki fragments.
3) Replication initiates at specific sites called replication origins that are recognized by origin-binding proteins. Eukaryotes have multiple origins per chromosome while prokaryotes have a single origin.
It concludes by
Variation in chromosome structure and number chapter 8Arshad Al-Ghafour
This document summarizes different types of variation in chromosome structure and number, as seen through cytogenetic analysis. It describes chromosomal aberrations such as deficiencies/deletions, duplications, inversions, and translocations that can occur through mutations or errors in meiosis. While most structural changes have no effect, some can impact phenotype depending on the genes involved. Duplications can provide raw material for gene families over generations as duplicated genes accumulate mutations and take on specialized functions.
Variation in chromosome structure and number chapter 8Arshad Al-Ghafour
This document summarizes variations in chromosome structure and number that can occur, including deficiencies, duplications, inversions, translocations, and changes in ploidy. It discusses how cytogenetic techniques are used to detect these variations and explains that while many have no effect, some can cause genetic abnormalities or disorders. It provides examples like Down syndrome that result from a specific aneuploidy.
This document discusses classification and viruses. It describes how phylogenies are based on homologous structures in living organisms that provide evidence of common ancestry. It also discusses how molecular biology is a powerful tool in systematics, allowing phylogenetic hypotheses to be developed based on molecular comparisons. Viruses can integrate their DNA into host cells and remain latent for long periods. Bacteria can also transfer genes through transformation, transduction, or conjugation.
The document summarizes key concepts about DNA and genetics, including:
1) DNA was identified as the genetic material through experiments showing it could be transformed between bacteria.
2) DNA and RNA are polymers composed of nucleotides containing nitrogenous bases, phosphate groups, and sugars.
3) DNA replication is semiconservative and involves unwinding the DNA double helix, adding complementary nucleotides, and rejoining to form two new DNA molecules.
4) Genes specify the sequence of amino acids in proteins through transcription of DNA to mRNA and translation of mRNA to proteins with the help of tRNAs and ribosomes.
The document summarizes key concepts about DNA and genetics, including:
1) DNA was identified as the genetic material through experiments showing it could be transferred between bacteria to cause heritable changes.
2) DNA and RNA are polymers composed of nucleotides containing nitrogenous bases, phosphate groups, and a pentose sugar.
3) DNA replication is semiconservative and involves unwinding the DNA double helix, adding complementary nucleotides, and rejoining to form two new DNA molecules.
4) Genes specify the sequence of amino acids in proteins through transcription of DNA to mRNA and translation of mRNA to proteins with the help of tRNA and ribosomes.
The document discusses gene transcription and RNA processing in bacteria and eukaryotes. It covers the key steps and mechanisms of transcription, including promoters, initiation, elongation, and termination. In eukaryotes, transcription is more complex due to larger genomes, cellular complexity, and need for precise gene regulation in different cell types. The three classes of RNA polymerases and their roles are described, as well as sequences involved in eukaryotic gene promoters.
The document discusses gene transcription and RNA modification in bacteria and eukaryotes. In bacteria, transcription involves three main stages - initiation, elongation, and termination. Initiation requires the RNA polymerase holoenzyme binding to promoter sequences and recruiting sigma factors. Termination can occur via rho-dependent or rho-independent mechanisms. Eukaryotic transcription is more complex, utilizing three RNA polymerases and involving regulatory elements, the TATA box, and general transcription factors to direct transcription.
Chapter03 cell structure and genetic controlnizam5007
The document summarizes the structure and functions of eukaryotic cells. It describes the key components of cells, including the plasma membrane, cytoplasm, organelles like the nucleus, mitochondria and lysosomes, and genetic material like DNA and RNA. It explains how cells carry out functions like transport of materials, protein synthesis, and genetic transcription to control cell activities.
This document provides an overview of microbial genetics concepts. It defines key terms like genetics, genes, chromosomes, and genomes. It describes the structure of DNA and the processes of DNA replication, transcription, and translation. It explains how genetic material is inherited vertically but can also be transferred horizontally between organisms through transformation, transduction, and conjugation. Mechanisms of genetic regulation, mutation, and repair are also summarized. The document uses diagrams and tables to illustrate these fundamental concepts in microbial genetics.
Recombinant DNA technology allows DNA from different sources to be combined through molecular biology techniques. DNA segments are recombined outside of living cells and can then enter a host cell and replicate. This technology was developed in 1973 and allows genes to be transferred between organisms. Recombinant DNA is made through various methods like transformation, phage introduction, or non-bacterial transformation which insert DNA into vectors that are then taken up by host cells. This technology is used to produce human proteins like insulin in bacteria for medical purposes. Safety issues involve ensuring recombinant DNA does not escape the laboratory.
Recombinant DNA (rDNA) refers to DNA created outside living cells by joining DNA from multiple sources. Common techniques for creating rDNA include restriction enzymes to cut DNA strands, ligation to join strands, and transformation or transfection to introduce rDNA into host cells. Vectors like plasmids, viruses, and artificial chromosomes are often used to replicate and express rDNA in host cells. rDNA techniques have applications in gene cloning, DNA sequencing, genetic engineering of plants and animals, and gene therapy to treat diseases.
1. Experiments by Griffith, Avery, MacLeod, and McCarty provided evidence that DNA is the genetic material, carrying hereditary information from parents to offspring.
2. Watson and Crick discovered that DNA has a double helix structure, with nucleotides containing complementary bases (A-T and G-C) that bond the two strands together.
3. The double helix structure explained how DNA can replicate precisely by unwinding and each strand serving as a template for a new complementary strand.
The document discusses the molecular structure of genes and chromosomes. It describes how DNA is organized into chromosomes, which contain both protein-coding genes and non-coding sequences. Genes contain exons and introns, and in eukaryotes genes are further organized into transcription units. Chromatin compacts the DNA into nucleosomes and higher-order structures like the 30nm fiber. Overall the document provides an overview of the molecular organization and components that make up eukaryotic genes and chromosomes.
The document discusses recombinant DNA technology. It begins by explaining that recombinant DNA is formed by joining DNA molecules or fragments from different sources. This technology has proven valuable in medicine, agriculture, industry and more. Key techniques discussed include using restriction enzymes to cut DNA at specific sequences, generating sticky or blunt ends, and joining DNA fragments together with DNA ligase to form recombinant DNA. The document also summarizes cloning recombinant DNA in bacteria using vectors like plasmids or cloning in eukaryotic cells using yeast artificial chromosomes. It describes amplification of DNA by cloning in cells or by polymerase chain reaction (PCR).
1. Bacterial genetics follows the same principles as other organisms, with bacteria reproducing asexually and passing genetic traits from parents to offspring.
2. DNA was discovered to be the genetic material through experiments like Griffith's, which showed that killed pneumococci could transfer genetic material to live pneumococci.
3. Bacteria have mechanisms for horizontal gene transfer including transformation, transduction, and conjugation. Conjugation involves direct contact between bacteria and transfer of plasmids which can carry antibiotic resistance or other genes.
This document discusses the potential role of ketogenic diets in eliminating or reducing the need for medical treatment in various diseases. It summarizes that ketogenic diets, which are very low in carbohydrates and higher in fats, induce a metabolic state called ketosis. Studies show that ketosis may help treat diseases like epilepsy, obesity, diabetes, and neurological and cardiovascular conditions by improving metabolic pathways and biomarkers. The document reviews the evidence and possible mechanisms for how ketogenic diets may help treat diseases, including reducing appetite and fat accumulation, improving lipid profiles, and reducing insulin resistance. However, more research is still needed to fully understand their long-term effects and therapeutic potential.
Dextropropoxyphene is an opioid analgesic used to treat mild to moderate pain. It acts on opioid receptors in the brain and spinal cord to reduce pain perception and increase tolerance. While it can be effective for its approved uses, it also carries risks of dependency and cardiac side effects when taken in high doses or combined with other central nervous system depressants like alcohol. A clinical study was conducted of 60 patients taking dextropropoxyphene to treat pain, depression, or other conditions. Most patients reported significant relief of symptoms with no side effects after 3 days of treatment. However, dextropropoxyphene must be prescribed judiciously due to its risks and potential for abuse.
Dextroprorpoxyphene is an opioid analgesic used to treat mild pain, cough, and muscle cramps. It acts as an agonist at mu-opioid receptors in the brain and gastrointestinal tract, reducing the perception of pain. However, it can cause dependency among recreational users and has a narrow therapeutic index. A clinical study of 60 patients compared the effects of dextroprorpoxyphene to traditional non-opioid drugs for various conditions like pain, depression, and bronchitis. The study aimed to evaluate dextroprorpoxyphene's adverse effects and judicious use.
This document summarizes the nutritional benefits of milk, particularly buffalo milk. It discusses how milk is an important source of nutrients worldwide. Buffalo milk specifically is highlighted as it is high in proteins, calcium, vitamins, and minerals that are important for bone, heart, and overall health. While milk can be beneficial, it also contains saturated fat, so the document recommends consuming milk in moderation as part of a balanced diet.
The document discusses various topics related to the genetic code, including:
1. The genetic code is degenerate, meaning many amino acids are specified by more than one codon. Wobble in the anticodon allows one tRNA to recognize multiple codons.
2. Three rules govern the genetic code: codons are read in groups of three in the 5' to 3' direction without gaps or overlaps.
3. Suppressor mutations can reside in the same gene or a different gene and suppress the effects of mutations by producing functional proteins.
Vitamin C plays an important role in the nervous system. It reaches high concentrations in neurons due to the SVCT2 transporter. In the brain, vitamin C acts as an antioxidant, helps form myelin sheaths, and protects against toxins. It is also involved in neurotransmitter synthesis and synaptic function. Vitamin C enters the brain through the choroid plexus into the cerebrospinal fluid and then into brain cells, maintaining high concentrations despite low blood levels. It has various roles in brain function and antioxidant defenses in the central nervous system.
This document discusses the health effects of caffeine consumption from coffee. It finds that moderate daily caffeine intake of up to 400 mg per day is not generally associated with adverse health effects in healthy adults. However, some groups like pregnant women and children may be more sensitive to caffeine and should limit their intake to under 300 mg and 2.5 mg per kg of body weight, respectively, to avoid potential negative effects. While caffeine has some stimulant effects, coffee also contains antioxidants and compounds that may provide health benefits when consumed in moderation.
1. DNA replication is the process by which a cell makes an identical copy of its DNA during cell division. It is a highly regulated and accurate process that occurs in all living organisms.
2. There are three proposed modes of DNA replication: conservative, semi-conservative, and dispersive. Experiments provided evidence that semi-conservative replication, where each parent strand acts as a template for a new partner strand, is how DNA replication occurs.
3. DNA replication requires several enzymes, including DNA polymerases, to unwind and copy the DNA double helix. In eukaryotes, DNA replication occurs at multiple replication origins along linear chromosomes, while prokaryotes replicate from a single origin on circular chromosomes
This document discusses regulation of gene expression in eukaryotes. It describes six main levels of control: transcription, RNA processing, mRNA transport, mRNA translation, mRNA degradation, and protein degradation. Key differences between prokaryotic and eukaryotic gene expression are explained, such as eukaryotes possessing nuclei and more complex regulation. Examples of short-term regulation including the GAL gene pathway in yeast and hormone response are provided.
This document provides an introduction to glycobiology and glycoproteins. It defines key terms like glycoproteins, glycosylation, and lectins. It describes the different types of glycoprotein linkages and classes. The roles and functions of glycoproteins are discussed, as well as the sugars commonly found in glycoproteins. Methods for studying glycoproteins like lectins, glycosidases, and mass spectrometry are also summarized.
Replication,transcription,translation complete the central dogma of life.How mRNA,tRNA,rRNA act on ribosomes for protein synthesis.Difference between eukaryotes and prokaryotes
Gene knock out technology involves replacing or disrupting an existing gene with artificial DNA to study gene function. The first knockout mouse was created in 1989. Knockout mice and microorganisms are commonly used animal models for studying genes in the laboratory. The procedure involves isolating the target gene, engineering a new DNA sequence with a marker gene, introducing this into stem cells via electroporation, and breeding mice with the knocked out gene. Knockout technology allows determining gene functions, creating mouse models of human diseases, and characterizing genetic regulatory regions.
The liver is a vital organ that performs many essential functions related to digestion, metabolism, immunity, and storage of nutrients. It has an incredible capacity for regeneration. The liver is located in the right upper quadrant of the abdominal cavity and is connected to two large blood vessels - the hepatic artery and portal vein. Radiographic studies like ultrasonography, CT, and MRI can detect changes associated with cirrhosis like nodularity, ascites, and varices, but liver biopsy remains the diagnostic standard.
This document summarizes research on the role of calcium ions in glucagon secretion by pancreatic alpha cells. It discusses studies showing that omitting extracellular calcium can paradoxically increase glucagon secretion in the presence of glucose or nutrients like arginine. It also notes that calcium plays both an inhibitory and permissive role, as calcium deprivation prevents arginine from stimulating glucagon release at low glucose levels but not high glucose levels. The document reviews how calcium channel blockers like verapamil can increase glucagon output at low glucose but decrease it at high glucose or with arginine stimulation. Finally, it discusses similarities in the effects of calcium omission on the responses of alpha cells to glucose levels or the nutrient 2-ketois
This document summarizes two methods for mapping DNA-protein interactions: DNase I footprinting and DMS footprinting. DNase I footprinting involves digesting DNA with DNase I after protein binding, which will be protected by the protein. DMS footprinting uses dimethyl sulfate to modify purines, which will be protected by bound protein. The document also reviews mechanisms of regulation of the lac and tryptophan operons, including activation of lac by cAMP-CAP and attenuation control of tryptophan based on tryptophan levels.
This document discusses various applications of radioactive isotopes. It begins by introducing radioisotope tracers and why they are ideal for tracking materials through complex processes. Only a small number of radioactive atoms are needed to be detectable. It then discusses specific applications such as medical uses of short-lived isotopes to image organs, using tracers to detect leaks, and radioactive dating methods like carbon-14 dating. The document concludes by mentioning radioisotope thermoelectric generators use radioactive decay to generate electricity and have been used to power spacecraft.
Radiation can be ionizing or non-ionizing. Ionizing radiation has enough energy to remove electrons from atoms and molecules and includes alpha particles, beta particles, gamma rays, x-rays, and neutrons. Non-ionizing radiation does not have enough energy to ionize but can excite electrons. Radiation is quantified by activity (disintegrations per second), exposure (energy deposited in air), absorbed dose (energy absorbed per mass), and biologically equivalent dose. Different types of ionizing radiation interact differently with tissues depending on their mass and charge. Acute radiation exposure can cause sickness and death while long-term effects include increased cancer risks and organ damage.
DNA vaccines work by injecting a plasmid containing a gene that codes for a pathogen's antigen. This allows a person's cells to produce the antigen and induce an immune response. DNA vaccines offer advantages over traditional vaccines like eliciting both antibody and T cell responses without using live or killed pathogens. However, DNA vaccines also present risks like genetic integration and autoimmunity that require further research. Current clinical trials show promise for DNA vaccines against viruses, but none have yet been approved for human use.
This document discusses various types of genetic mutations and modifications, including:
- Point mutations such as base pair substitutions that can be silent, cause a different amino acid (missense), or a stop codon (nonsense)
- Insertions/deletions of base pairs that can cause frameshift mutations
- Triplet repeats as seen in Huntington's disease
- Chromosomal abnormalities like variations in number (Down syndrome), deletions, translocations, duplications, and inversions.
The document explores examples like sickle cell anemia and how genetic modifications could lead to "designer babies" in the future.
More from GGS Medical College/Baba Farid Univ.of Health Sciences. (20)
5. Figure 10.1 General structure of viruses
10-5
Bacteriophages may also contain a sheath, base plate and
tail fibers
Refer to Figure 9.4
Lipid bilayer
Picked up when
virus leaves host cell