1. The document discusses the history and structure of nucleic acids DNA and RNA. It describes their discovery in the 1860s and the elucidation of DNA's double helix structure in 1953 by Watson, Crick, Wilkins and Franklin.
2. DNA is made of nucleotides containing deoxyribose, phosphate groups and nitrogenous bases that form base pairs between adenine-thymine and guanine-cytosine. RNA is similar but contains ribose and pairs uracil instead of thymine.
3. The document categorizes RNA into coding mRNA and non-coding types including rRNA, tRNA, snRNA, snoRNA, miRNA and lncRNA that have important structural and functional roles such
DNA supercoiling occurs when the DNA double helix is over- or under-wound, known as positive and negative supercoiling respectively. The degree of supercoiling is numerically expressed using the linking number which accounts for twists and writhes in the DNA helix. Topoisomerases are enzymes that relieve torsional strain in supercoiled DNA by introducing nicks in one or both strands, allowing the strands to pass through one another and change the linking number.
DNA replication in prokaryotes occurs through a semi-conservative process where each daughter cell inherits one old and one new DNA strand. Replication begins at the origin of replication and proceeds bidirectionally. It involves three main stages - initiation, elongation, and termination. Initiation requires unwinding of the DNA duplex by helicase at the origin. Elongation is carried out by DNA polymerase III which synthesizes new DNA strands along the leading strand continuously and in short fragments along the lagging strand. Termination occurs when the replication forks from opposite directions meet.
This document discusses DNA replication in prokaryotes and eukaryotes. It provides an overview of the key steps and enzymes involved in DNA replication for both prokaryotes and eukaryotes. For prokaryotes, it describes initiation at the origin of replication involving DNA A protein, elongation by DNA polymerase III, and termination when replication forks meet. For eukaryotes, it outlines initiation involving pre-replication complexes, elongation involving leading and lagging strand synthesis, and the various enzymes involved such as DNA polymerases and helicases.
The document discusses DNA replication. It begins by describing the structure of DNA as a double helix with two antiparallel polynucleotide chains held together by hydrogen bonds between complementary bases. It then discusses the process of DNA replication, noting that it is semi-conservative and involves unwinding of the DNA strands followed by synthesis of new complementary strands. The key enzymes involved are helicase, primase, DNA polymerase III, and DNA ligase. Replication proceeds bidirectionally from an origin of replication and terminates at specific sites. Comparison is made between prokaryotic and eukaryotic replication, highlighting differences in enzymes used, speed, and number of origins of replication.
This document discusses nucleic acids, DNA, RNA, their structures and functions. It describes that nucleic acids are made up of nucleotides containing a sugar, phosphate and a base. The bases in DNA are adenine, guanine, cytosine and thymine, while in RNA thymine is replaced with uracil. It explains the primary and secondary structures of DNA including the double helix structure. It also summarizes the central dogma of biology regarding DNA replication, transcription and translation of DNA to mRNA to proteins. The document concludes with a discussion of mutations that can occur during DNA replication and an overview of cloning techniques.
The document summarizes the process of DNA replication in prokaryotic cells like E. coli. It describes the three main stages: initiation at the Ori C origin site involving DnaA and DnaB proteins, elongation where the leading strand is synthesized continuously and the lagging strand requires RNA primers, and termination when the replication forks meet specific termination sites and DnaB is released. DNA replication allows faithful copying of the parental DNA to produce two identical progeny DNA molecules.
Nucleic acids like DNA and RNA are composed of nucleotides, which contain a nitrogenous base (purine or pyrimidine), a 5-carbon sugar (ribose or deoxyribose), and one or more phosphate groups. Friedrich Miescher first isolated nucleic acids in 1869. DNA exists as a double-stranded helical structure, with the bases on one strand bonding with complementary bases on the other strand. The sugar-phosphate backbone of DNA contains alternating sugar and phosphate groups and runs in the same direction on both strands.
DNA supercoiling occurs when the DNA double helix is over- or under-wound, known as positive and negative supercoiling respectively. The degree of supercoiling is numerically expressed using the linking number which accounts for twists and writhes in the DNA helix. Topoisomerases are enzymes that relieve torsional strain in supercoiled DNA by introducing nicks in one or both strands, allowing the strands to pass through one another and change the linking number.
DNA replication in prokaryotes occurs through a semi-conservative process where each daughter cell inherits one old and one new DNA strand. Replication begins at the origin of replication and proceeds bidirectionally. It involves three main stages - initiation, elongation, and termination. Initiation requires unwinding of the DNA duplex by helicase at the origin. Elongation is carried out by DNA polymerase III which synthesizes new DNA strands along the leading strand continuously and in short fragments along the lagging strand. Termination occurs when the replication forks from opposite directions meet.
This document discusses DNA replication in prokaryotes and eukaryotes. It provides an overview of the key steps and enzymes involved in DNA replication for both prokaryotes and eukaryotes. For prokaryotes, it describes initiation at the origin of replication involving DNA A protein, elongation by DNA polymerase III, and termination when replication forks meet. For eukaryotes, it outlines initiation involving pre-replication complexes, elongation involving leading and lagging strand synthesis, and the various enzymes involved such as DNA polymerases and helicases.
The document discusses DNA replication. It begins by describing the structure of DNA as a double helix with two antiparallel polynucleotide chains held together by hydrogen bonds between complementary bases. It then discusses the process of DNA replication, noting that it is semi-conservative and involves unwinding of the DNA strands followed by synthesis of new complementary strands. The key enzymes involved are helicase, primase, DNA polymerase III, and DNA ligase. Replication proceeds bidirectionally from an origin of replication and terminates at specific sites. Comparison is made between prokaryotic and eukaryotic replication, highlighting differences in enzymes used, speed, and number of origins of replication.
This document discusses nucleic acids, DNA, RNA, their structures and functions. It describes that nucleic acids are made up of nucleotides containing a sugar, phosphate and a base. The bases in DNA are adenine, guanine, cytosine and thymine, while in RNA thymine is replaced with uracil. It explains the primary and secondary structures of DNA including the double helix structure. It also summarizes the central dogma of biology regarding DNA replication, transcription and translation of DNA to mRNA to proteins. The document concludes with a discussion of mutations that can occur during DNA replication and an overview of cloning techniques.
The document summarizes the process of DNA replication in prokaryotic cells like E. coli. It describes the three main stages: initiation at the Ori C origin site involving DnaA and DnaB proteins, elongation where the leading strand is synthesized continuously and the lagging strand requires RNA primers, and termination when the replication forks meet specific termination sites and DnaB is released. DNA replication allows faithful copying of the parental DNA to produce two identical progeny DNA molecules.
Nucleic acids like DNA and RNA are composed of nucleotides, which contain a nitrogenous base (purine or pyrimidine), a 5-carbon sugar (ribose or deoxyribose), and one or more phosphate groups. Friedrich Miescher first isolated nucleic acids in 1869. DNA exists as a double-stranded helical structure, with the bases on one strand bonding with complementary bases on the other strand. The sugar-phosphate backbone of DNA contains alternating sugar and phosphate groups and runs in the same direction on both strands.
Quaternary structure refers to the arrangement of multiple protein subunits into a single protein complex. Hemoglobin is a common example that is made of two alpha and two beta subunits. The subunits interact through hydrophobic interactions, hydrogen bonding, and other bonds. Globular proteins tend to have quaternary structure that clusters the subunits into a spherical shape, while fibrous proteins form long coils or sheets through interactions between subunits. Quaternary structure allows proteins to take on specialized functions beyond what individual subunits could achieve alone.
Nucleic acids like DNA and RNA are made of nucleotides and store genetic information. DNA is double-stranded and located in the nucleus, while RNA is single-stranded and found in the cytoplasm. Nucleotides consist of a phosphate, pentose sugar, and nitrogenous base. DNA uses complementary base pairing between adenine and thymine or cytosine and guanine to form its double helix structure.
The genetic code is the system by which nucleotide sequences in mRNA determine the amino acid sequences in proteins. The genetic code uses triplets of nucleotides called codons to specify which amino acid will be incorporated into the growing polypeptide chain. There are 64 possible codons but only 20 standard amino acids, so most amino acids have multiple codons. Three codons act as stop signals to end protein synthesis. The genetic code is nearly universal across all life due to its high degree of specificity and redundancy.
Protein phosphorylation is a post-translational modification that was first reported in 1906 and alters protein structure and function. It involves the addition of a covalently bound phosphate group to an amino acid residue on a protein by protein kinases. Phosphorylation can activate or deactivate proteins or modify their function. It is used in important cellular processes like metabolic enzyme regulation, receptor signaling, cell cycle control by cyclin-dependent kinases, and maintaining homeostasis.
- Crick proposed the "wobble hypothesis" to explain how more than one codon can direct the synthesis of a single amino acid, given there are fewer tRNAs than codons.
- The hypothesis suggests the third nucleotide in a codon is not as important in binding to the tRNA anticodon. The first two nucleotides specify the amino acid.
- At the wobble position, the third nucleotide in the codon can bind in non-standard ways ("wobble") to the first nucleotide in the anticodon, allowing a single tRNA to bind to multiple codons and explain the degeneracy of the genetic code.
This document discusses various methods for determining the amino acid sequence of proteins, including:
- Edman degradation, which sequentially removes amino acids from the N-terminus. Up to 60 amino acids can typically be determined.
- Mass spectrometry techniques like MALDI that help determine the mass and sequence of protein fragments.
- Enzymatic cleavage techniques using enzymes like trypsin to break proteins into smaller fragments that can then be sequenced.
This document provides information about nucleic acids DNA and RNA. It discusses the molecular structure of DNA including its double helix structure and composition of nucleotides. It also describes the four types of nucleotides in DNA and different types of DNA structures. The document summarizes RNA including its molecular structure, types of ribonucleotides, and three main types of RNA - mRNA, rRNA and tRNA. It highlights the significance of DNA as the genetic material and RNA's role in protein synthesis.
This document summarizes lysosomes and peroxisomes. Lysosomes are spherical organelles that contain enzymes for digesting molecules. They break down materials from both inside and outside the cell. Peroxisomes contain enzymes that produce and break down hydrogen peroxide. They are involved in lipid metabolism and synthesis. Both organelles have a single membrane and matrix containing enzymes. Lysosomes digest materials through enzymatic reactions while peroxisomes participate in important metabolic processes like fatty acid breakdown and bile acid synthesis.
1) DNA replication begins with the unwinding of the DNA double helix at an origin of replication site.
2) This forms a replication fork with leading and lagging strands that are copied semi-conservatively to produce two identical copies of DNA.
3) RNA primers, DNA polymerases, helicase and single-strand binding proteins work together to separate the strands and synthesize new DNA in the 5’-3’ direction along the template.
This document summarizes DNA replication in eukaryotic cells. It describes that replication occurs through replicons to overcome the slower polymerases. Replication is initiated at specific sites called autonomous replicating sequences (ARS) where the origin recognition complex (ORC) binds. Elongation uses DNA polymerases α, δ, and ε and occurs semi-discontinuously with Okazaki fragments on the lagging strand. Termination involves removing RNA primers with RNase H and sealing fragments with DNA ligase. Multiple enzymes are involved in each phase including MCM helicase, primase, DNA ligase, and DNA polymerases.
The document summarizes Ramachandran plots, which visualize backbone dihedral angles ψ against φ of amino acid residues in protein structures. Ramachandran plots show sterically allowed and disallowed conformations based on calculations using van der Waals radii and bond angles. Specific regions of the plot correspond to different secondary structures like alpha helices and beta sheets. The plots can also be used to validate protein structures by comparing observed dihedral angles to expected allowed regions.
This document discusses amino acids and proteins. It defines that amino acids are the monomer units that make up proteins and polypeptides. There are 300 amino acids found in nature but only 20 are used in protein synthesis. Proteins perform important structural, catalytic and regulatory functions in the body. The structure of proteins involves four levels: primary, secondary, tertiary and quaternary. Denaturation involves the unfolding of protein structure through physical or chemical means.
Protein structure can be described at several levels of organization. The primary structure is the amino acid sequence, while the secondary structure describes local patterns like alpha helices and beta sheets formed by hydrogen bonds. Tertiary structure refers to the overall 3D shape of a single polypeptide chain. Quaternary structure involves the arrangement of multiple protein subunits. Together these organizational levels allow proteins to carry out their diverse functions in the cell.
This document discusses different DNA binding motifs that allow proteins to interact with DNA without disrupting the hydrogen bonds between the DNA bases. It describes several conserved structural motifs common to many DNA binding proteins, including the helix-turn-helix motif, zinc finger domains, and leucine zipper domains. The helix-turn-helix motif contains two short alpha helices separated by a beta turn. Zinc finger domains use cysteine or histidine residues to coordinate a zinc ion, stabilizing their structure. Leucine zipper domains contain repeated leucine residues that allow dimerization of regulatory proteins.
Protein sequencing involves determining the order of amino acids in a protein chain. [1] Edman degradation is commonly used for N-terminal sequencing and involves labeling the N-terminal amino acid, removing it, and identifying it through chromatography and mass spectrometry. [2] The protein must first be purified and digested before Edman degradation can begin. [3] Mass spectrometry is used to analyze the separated amino acid derivatives and identify the sequence.
This document summarizes post-transcriptional modifications in eukaryotes. It discusses how eukaryotic mRNA undergoes processing, including capping, splicing to remove introns, and polyadenylation. Splicing requires snRNPs and the spliceosome to recognize splice sites. Alternative splicing allows one gene to code for multiple proteins. tRNA and rRNA also undergo processing as they mature, including modification of bases and removal of sequences. Final mature mRNA, tRNA, and rRNA are then ready for translation.
DNA is composed of nucleotides that contain nitrogenous bases, deoxyribose sugar, and phosphate groups. The bases adenine and thymine pair together via two hydrogen bonds, while cytosine and guanine pair together via three hydrogen bonds. Watson and Crick discovered that DNA exists as a double helix with two anti-parallel strands coiled around a common axis, with the bases pairing according to Chargaff's rules. Their model explained experimental X-ray crystallography data and is universally accepted as the structure of DNA.
The genetic code refers to the genetic information carried by living cells that is made up of triplets of nitrogenous bases called codons, which specify the 20 standard amino acids during protein synthesis. The genetic code is universal across all species, with each codon representing a single amino acid in an unambiguous way. Some codons initiate protein formation, some terminate it, and frameshift mutations can occur if the genetic code is altered.
The document discusses protein backbone flexibility and the Ramachandran plot. It provides information on:
1) The phi and psi torsion angles that describe rotations around peptide bonds in the protein backbone and allow for different protein conformations.
2) How the Ramachandran plot maps allowed and disallowed phi-psi angle combinations based on steric clashes, and observed combinations in real proteins.
3) The plot serves as an indicator of protein structure quality by showing if residues fall in allowed regions. Understanding phi-psi angles helps predict protein folding.
DNA has a double helical structure with two polynucleotide chains coiled around each other. Watson and Crick proposed this double helical model in 1953 based on Chargaff's rules that the amount of adenine equals thymine and guanine equals cytosine. The backbone of DNA is made up of alternating sugar and phosphate groups while the bases pair with each other between the chains through hydrogen bonds - adenine pairs with thymine and guanine pairs with cytosine.
Nucleic acids are biopolymers composed of nucleotides as repeating units. DNA contains the genetic instructions for living organisms, while RNA assists in decoding this information. A nucleotide contains a phosphate group, a sugar (ribose in RNA and deoxyribose in DNA), and a nitrogenous base. DNA exists as a double helix with base pairing between adenine-thymine and guanine-cytosine. It undergoes replication to make copies for cell division. During transcription, RNA is synthesized from a DNA template, and translation follows to produce proteins from mRNA instructions. Mutation, control of gene expression, and the central dogma of molecular biology maintain and regulate the flow of genetic information.
Quaternary structure refers to the arrangement of multiple protein subunits into a single protein complex. Hemoglobin is a common example that is made of two alpha and two beta subunits. The subunits interact through hydrophobic interactions, hydrogen bonding, and other bonds. Globular proteins tend to have quaternary structure that clusters the subunits into a spherical shape, while fibrous proteins form long coils or sheets through interactions between subunits. Quaternary structure allows proteins to take on specialized functions beyond what individual subunits could achieve alone.
Nucleic acids like DNA and RNA are made of nucleotides and store genetic information. DNA is double-stranded and located in the nucleus, while RNA is single-stranded and found in the cytoplasm. Nucleotides consist of a phosphate, pentose sugar, and nitrogenous base. DNA uses complementary base pairing between adenine and thymine or cytosine and guanine to form its double helix structure.
The genetic code is the system by which nucleotide sequences in mRNA determine the amino acid sequences in proteins. The genetic code uses triplets of nucleotides called codons to specify which amino acid will be incorporated into the growing polypeptide chain. There are 64 possible codons but only 20 standard amino acids, so most amino acids have multiple codons. Three codons act as stop signals to end protein synthesis. The genetic code is nearly universal across all life due to its high degree of specificity and redundancy.
Protein phosphorylation is a post-translational modification that was first reported in 1906 and alters protein structure and function. It involves the addition of a covalently bound phosphate group to an amino acid residue on a protein by protein kinases. Phosphorylation can activate or deactivate proteins or modify their function. It is used in important cellular processes like metabolic enzyme regulation, receptor signaling, cell cycle control by cyclin-dependent kinases, and maintaining homeostasis.
- Crick proposed the "wobble hypothesis" to explain how more than one codon can direct the synthesis of a single amino acid, given there are fewer tRNAs than codons.
- The hypothesis suggests the third nucleotide in a codon is not as important in binding to the tRNA anticodon. The first two nucleotides specify the amino acid.
- At the wobble position, the third nucleotide in the codon can bind in non-standard ways ("wobble") to the first nucleotide in the anticodon, allowing a single tRNA to bind to multiple codons and explain the degeneracy of the genetic code.
This document discusses various methods for determining the amino acid sequence of proteins, including:
- Edman degradation, which sequentially removes amino acids from the N-terminus. Up to 60 amino acids can typically be determined.
- Mass spectrometry techniques like MALDI that help determine the mass and sequence of protein fragments.
- Enzymatic cleavage techniques using enzymes like trypsin to break proteins into smaller fragments that can then be sequenced.
This document provides information about nucleic acids DNA and RNA. It discusses the molecular structure of DNA including its double helix structure and composition of nucleotides. It also describes the four types of nucleotides in DNA and different types of DNA structures. The document summarizes RNA including its molecular structure, types of ribonucleotides, and three main types of RNA - mRNA, rRNA and tRNA. It highlights the significance of DNA as the genetic material and RNA's role in protein synthesis.
This document summarizes lysosomes and peroxisomes. Lysosomes are spherical organelles that contain enzymes for digesting molecules. They break down materials from both inside and outside the cell. Peroxisomes contain enzymes that produce and break down hydrogen peroxide. They are involved in lipid metabolism and synthesis. Both organelles have a single membrane and matrix containing enzymes. Lysosomes digest materials through enzymatic reactions while peroxisomes participate in important metabolic processes like fatty acid breakdown and bile acid synthesis.
1) DNA replication begins with the unwinding of the DNA double helix at an origin of replication site.
2) This forms a replication fork with leading and lagging strands that are copied semi-conservatively to produce two identical copies of DNA.
3) RNA primers, DNA polymerases, helicase and single-strand binding proteins work together to separate the strands and synthesize new DNA in the 5’-3’ direction along the template.
This document summarizes DNA replication in eukaryotic cells. It describes that replication occurs through replicons to overcome the slower polymerases. Replication is initiated at specific sites called autonomous replicating sequences (ARS) where the origin recognition complex (ORC) binds. Elongation uses DNA polymerases α, δ, and ε and occurs semi-discontinuously with Okazaki fragments on the lagging strand. Termination involves removing RNA primers with RNase H and sealing fragments with DNA ligase. Multiple enzymes are involved in each phase including MCM helicase, primase, DNA ligase, and DNA polymerases.
The document summarizes Ramachandran plots, which visualize backbone dihedral angles ψ against φ of amino acid residues in protein structures. Ramachandran plots show sterically allowed and disallowed conformations based on calculations using van der Waals radii and bond angles. Specific regions of the plot correspond to different secondary structures like alpha helices and beta sheets. The plots can also be used to validate protein structures by comparing observed dihedral angles to expected allowed regions.
This document discusses amino acids and proteins. It defines that amino acids are the monomer units that make up proteins and polypeptides. There are 300 amino acids found in nature but only 20 are used in protein synthesis. Proteins perform important structural, catalytic and regulatory functions in the body. The structure of proteins involves four levels: primary, secondary, tertiary and quaternary. Denaturation involves the unfolding of protein structure through physical or chemical means.
Protein structure can be described at several levels of organization. The primary structure is the amino acid sequence, while the secondary structure describes local patterns like alpha helices and beta sheets formed by hydrogen bonds. Tertiary structure refers to the overall 3D shape of a single polypeptide chain. Quaternary structure involves the arrangement of multiple protein subunits. Together these organizational levels allow proteins to carry out their diverse functions in the cell.
This document discusses different DNA binding motifs that allow proteins to interact with DNA without disrupting the hydrogen bonds between the DNA bases. It describes several conserved structural motifs common to many DNA binding proteins, including the helix-turn-helix motif, zinc finger domains, and leucine zipper domains. The helix-turn-helix motif contains two short alpha helices separated by a beta turn. Zinc finger domains use cysteine or histidine residues to coordinate a zinc ion, stabilizing their structure. Leucine zipper domains contain repeated leucine residues that allow dimerization of regulatory proteins.
Protein sequencing involves determining the order of amino acids in a protein chain. [1] Edman degradation is commonly used for N-terminal sequencing and involves labeling the N-terminal amino acid, removing it, and identifying it through chromatography and mass spectrometry. [2] The protein must first be purified and digested before Edman degradation can begin. [3] Mass spectrometry is used to analyze the separated amino acid derivatives and identify the sequence.
This document summarizes post-transcriptional modifications in eukaryotes. It discusses how eukaryotic mRNA undergoes processing, including capping, splicing to remove introns, and polyadenylation. Splicing requires snRNPs and the spliceosome to recognize splice sites. Alternative splicing allows one gene to code for multiple proteins. tRNA and rRNA also undergo processing as they mature, including modification of bases and removal of sequences. Final mature mRNA, tRNA, and rRNA are then ready for translation.
DNA is composed of nucleotides that contain nitrogenous bases, deoxyribose sugar, and phosphate groups. The bases adenine and thymine pair together via two hydrogen bonds, while cytosine and guanine pair together via three hydrogen bonds. Watson and Crick discovered that DNA exists as a double helix with two anti-parallel strands coiled around a common axis, with the bases pairing according to Chargaff's rules. Their model explained experimental X-ray crystallography data and is universally accepted as the structure of DNA.
The genetic code refers to the genetic information carried by living cells that is made up of triplets of nitrogenous bases called codons, which specify the 20 standard amino acids during protein synthesis. The genetic code is universal across all species, with each codon representing a single amino acid in an unambiguous way. Some codons initiate protein formation, some terminate it, and frameshift mutations can occur if the genetic code is altered.
The document discusses protein backbone flexibility and the Ramachandran plot. It provides information on:
1) The phi and psi torsion angles that describe rotations around peptide bonds in the protein backbone and allow for different protein conformations.
2) How the Ramachandran plot maps allowed and disallowed phi-psi angle combinations based on steric clashes, and observed combinations in real proteins.
3) The plot serves as an indicator of protein structure quality by showing if residues fall in allowed regions. Understanding phi-psi angles helps predict protein folding.
DNA has a double helical structure with two polynucleotide chains coiled around each other. Watson and Crick proposed this double helical model in 1953 based on Chargaff's rules that the amount of adenine equals thymine and guanine equals cytosine. The backbone of DNA is made up of alternating sugar and phosphate groups while the bases pair with each other between the chains through hydrogen bonds - adenine pairs with thymine and guanine pairs with cytosine.
Nucleic acids are biopolymers composed of nucleotides as repeating units. DNA contains the genetic instructions for living organisms, while RNA assists in decoding this information. A nucleotide contains a phosphate group, a sugar (ribose in RNA and deoxyribose in DNA), and a nitrogenous base. DNA exists as a double helix with base pairing between adenine-thymine and guanine-cytosine. It undergoes replication to make copies for cell division. During transcription, RNA is synthesized from a DNA template, and translation follows to produce proteins from mRNA instructions. Mutation, control of gene expression, and the central dogma of molecular biology maintain and regulate the flow of genetic information.
Nucleic acids like DNA and RNA are essential for information transfer in cells. DNA is replicated with high fidelity to pass genetic information to daughter cells. The sequence of bases in DNA is transcribed into mRNA which is then translated into a protein sequence using tRNA and ribosomes. Nucleic acids are polymers of nucleotides containing a sugar, phosphate group, and nitrogenous base. The sequence of nucleotides determines the genetic code and proteins synthesized in cells.
Nucleic acids such as DNA and RNA are essential biological molecules found in the nuclei of living cells. DNA controls cellular functions and heredity by carrying the genetic instructions in its double-stranded structure. DNA is made up of nucleotides containing deoxyribose, phosphate groups, and organic bases (adenine, guanine, cytosine, thymine) that bond together in a double helix with base pairing between adenine-thymine and cytosine-guanine. RNA also carries out important cellular functions and exists in different types including mRNA, tRNA, and rRNA.
Both RNA and DNA are made of nucleotides and take similar shapes. Both contain five-carbon sugars, phosphate groups, and nucleobases (nitrogenous bases). They both play important roles in protein synthesis. DNA has the five-carbon sugar deoxyribose and RNA has the five-carbon sugar ribose, hence their names
Nucleic acids are polymers made of nucleotides that serve as the repository of genetic information. There are two main types of nucleic acids: DNA and RNA. DNA is found in cell nuclei and contains the genetic blueprint. RNA is found throughout the cell and assists in protein synthesis. A nucleotide contains a nitrogenous base (purine or pyrimidine), a 5-carbon sugar (deoxyribose in DNA and ribose in RNA), and one or more phosphate groups. Nucleotides bond together via phosphodiester linkages between the sugar and phosphate to form polynucleotide chains. DNA exists as a double helix with the bases on the inside bonded via hydrogen bonds in a complementary and antiparallel fashion
This document provides an introduction to genomics, proteomics, and comparative genomics. It discusses the central dogma of molecular biology involving DNA replication, transcription, and translation. It describes DNA and RNA structure and explains how genetic information flows from DNA to protein. The document also discusses genome sequencing, gene mapping, and how comparative analysis of genomes from different species can provide insights into evolutionary relationships and biological functions.
The document discusses nucleic acids, specifically DNA and RNA. It provides details on:
- DNA and RNA are polymers made of nucleotides consisting of a base, sugar, and phosphate. DNA contains the bases A, G, C, T while RNA contains A, G, C, U.
- The structure of DNA is a double helix with the bases pairing together on the inside and the sugar-phosphate backbones on the outside.
- RNA includes messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries genetic information from DNA, rRNA is a component of ribosomes, and tRNA delivers amino acids during protein synthesis.
- The central dogma of
Nucleic acids are macromolecules found in all living cells that contain genetic information. There are two main types of nucleic acids: DNA and RNA. In 1953, Watson and Crick proposed their famous double helix model for the structure of DNA based on X-ray crystallography data. Their model showed that DNA consists of two strands coiled around each other, with nucleotides on each strand pairing with each other through hydrogen bonds. Adenine pairs with thymine and guanine pairs with cytosine. This discovery established that DNA is the genetic material.
Types of nucliec acids, biosynthesis and catabolismShereen
1. The document discusses nucleic acids, their biosynthesis, and catabolism. It describes the two main types of nucleic acids - DNA and RNA, how they are synthesized through de novo and salvage pathways, and their components.
2. It provides details on the structures of DNA and RNA, including their nitrogenous bases, pentose sugars, and phosphate groups. DNA is double-stranded and found in the nucleus, while RNA exists in several forms and has roles in protein synthesis.
3. Nucleic acid catabolism and the roles of the different RNA types - mRNA, tRNA, and rRNA - in gene expression and protein synthesis are also summarized.
- Frederic Miesher first isolated nucleic acid from salmon sperm in 1869, naming it nuclein.
- In 1920, Jones proved there are two types of nucleic acids: DNA and RNA.
- In 1953, Watson and Crick used data from Franklin and others to discover that DNA is a double helix with complementary base pairing between strands.
Nucleic acids like DNA and RNA are long biopolymers composed of nucleotides. DNA stores genetic information in cells and is made up of deoxyribonucleotides arranged in a double helix structure. RNA is involved in protein synthesis and comes in several types including mRNA, tRNA, and rRNA. Nucleic acids have a primary structure defined by their linear sequence of nucleotides joined by phosphodiester bonds, and a secondary structure involving base pairing of nucleotides that gives them their characteristic helical shape.
Nucleic acids like DNA and RNA are long biopolymers composed of nucleotides. DNA stores genetic information in cells and is made up of deoxyribonucleotides arranged in a double helix structure. RNA is involved in protein synthesis and comes in several types including mRNA, tRNA, and rRNA. Nucleic acids have a primary structure defined by their linear sequence of nucleotides joined by phosphodiester bonds, and a secondary structure involving base pairing of nucleotides that gives them their characteristic helical shape.
Nucleic acids like DNA and RNA are long biopolymers composed of nucleotides. DNA stores genetic information in cells and is made up of deoxyribonucleotides arranged in a double helix structure. RNA is involved in protein synthesis and comes in several types including mRNA, tRNA, and rRNA. Nucleic acids have a primary structure defined by their linear sequence of nucleotides joined by phosphodiester bonds, and a secondary structure involving base pairing of nucleotides that gives them their characteristic helical shape.
Sumeet Jani gave a presentation on DNA structure and function. The presentation covered what DNA is, its composition including the nitrogenous bases of adenine, guanine, cytosine, thymine and uracil. It described DNA as a double helix with two complementary strands held together by hydrogen bonds between the bases. The structure allows DNA to efficiently store genetic information.
Nucleic acids are polymers of nucleotides linked by phosphodiester bonds. There are two types: DNA and RNA. DNA contains the genetic information and directs protein synthesis. It exists as a double helix with nucleotides paired through hydrogen bonds between complementary bases (A-T and G-C). RNA is single-stranded and also involved in protein synthesis.
Nucleic acids are polymers of nucleotides that store genetic information. There are two main types: DNA and RNA. A nucleotide contains a nitrogenous base, a pentose sugar (ribose in RNA and deoxyribose in DNA), and a phosphate group. DNA forms a double helix with base pairing between complementary nucleotides. RNA exists in various forms that aid in protein synthesis.
Friedrich Miescher discovered nucleic acids in 1869. There are two main types of nucleic acids: DNA and RNA. DNA is made of nucleotides containing the bases adenine, cytosine, guanine, and thymine. It takes the form of a double helix with the bases pairing between strands. In 1953, Watson and Crick proposed the double helix structure of DNA based on X-ray crystallography data. RNA is single-stranded and contains the bases adenine, cytosine, guanine, and uracil. There are several types of RNA including messenger RNA, ribosomal RNA, and transfer RNA that help in protein synthesis.
DNA and RNA are polymers composed of nucleotides containing nitrogenous bases, pentose sugars, and phosphate groups. DNA exists as a double helix with base pairing between strands. The discovery of the DNA double helix structure in 1953 revealed how genetic information is stored and replicated. RNA exists in various forms including mRNA, tRNA, and rRNA that aid in gene expression and protein synthesis. Nucleic acids have distinctive properties like UV absorption that allow for analysis of their structure and function.
Similar to Nucleic acids structure & function (20)
This document provides an introduction to animal cell culture by Dr. Anu P. Abhimannue. It discusses the history and development of animal cell culture from the early 20th century. It describes different types of animal cell culture such as primary versus secondary culture and finite versus continuous cell lines. It also discusses various cell culture methods like monolayer, suspension, types of culture vessels used and morphology of cultured cells. The document provides advantages and limitations of animal cell culture techniques.
This document discusses the organization of chromatin and DNA packaging in the cell nucleus. It describes four main levels of chromatin organization: 1) DNA wraps around histone proteins to form nucleosomes, the basic unit of chromatin, 2) Nucleosomes further organize into 30nm fibers, 3) The 30nm fibers then organize into looped domains, and 4) During cell division, the loops compact into mitotic chromosomes. Nucleosomes consist of about 150 base pairs of DNA wrapped around an octamer of core histone proteins, and act to tightly package DNA inside the nucleus.
DNA topology studies the geometric properties and spatial relationships of DNA that are unaffected by changes in shape or size. It includes phenomena like supercoiling, knots, and catenanes that involve the linking and twisting of the two DNA strands. DNA topology is characterized by parameters like the linking number, which represents the number of times the two strands are twisted around each other. Enzymes called topoisomerases regulate DNA topology by introducing temporary breaks in the DNA strands to allow strand passage and control supercoiling levels.
Three key experiments helped resolve the question of whether DNA or protein served as the genetic material. Griffith's transformation experiment showed that heat-killed bacteria could transform live bacteria, indicating a heritable factor. Avery, MacLeod and McCarty's experiments showed that the transforming principle was destroyed by DNAase, showing it was DNA. Hershey and Chase used radioactively labeled bacteriophage to infect bacteria, finding that only the label in the phage's DNA entered the bacterial cells, demonstrating that DNA rather than protein transfers genetic information. These experiments established DNA as the genetic material.
Degradative plasmids & superbug for oil spillsAnu Sreejith
The document discusses the development of a "superbug" bacterium for oil spill cleanup. It describes how researchers genetically engineered Pseudomonas putida by transferring plasmids containing genes for degrading various hydrocarbons. This created a strain that could break down compounds like camphor, octane, xylene and naphthalene. The superbug was the first genetically engineered microorganism to be patented. While genetically engineered microbes show promise for bioremediation, they also risk disturbing ecosystems if released.
Biodiesel is a renewable fuel made from vegetable oils and animal fats through a chemical process called transesterification, where the oil reacts with an alcohol like methanol in the presence of a catalyst to produce biodiesel and glycerin. It can be used as an alternative to conventional diesel fuel or blended with petroleum diesel in any ratio. Some benefits of biodiesel include being biodegradable, producing lower emissions than petroleum diesel, and not requiring engine modifications. The document discusses the transesterification process used to produce biodiesel from oils as well as some potential disadvantages like higher production costs compared to petroleum diesel.
The document discusses bio-derived polyethylene, which is polyethylene made from ethanol produced by fermenting biomass rather than from petroleum. It can be produced through the same process as traditional polyethylene. The ethanol is converted to ethylene then polymerized into bio-derived polyethylene. This is more environmentally friendly as it sequesters carbon dioxide, but relies on intensive agriculture that may contribute to deforestation. It can be used to make products like carry bags, films and bottles.
This document discusses single cell protein (SCP) production and advantages. It describes how microorganisms like algae, fungi and bacteria can be used to produce SCP. The key steps in SCP production are selection of a suitable microbial strain, media preparation, fermentation, and separation and downstream processing. A variety of substrates can be used including waste materials, agricultural byproducts, and carbon dioxide. Common microorganisms used are fungi like Fusarium and yeasts like Saccharomyces. The final product can be used as a protein supplement for humans or animals.
This document discusses apoptosis, or programmed cell death. It defines apoptosis as the demise of cells through programmed cell death and describes it as being characterized by well-orchestrated events. It notes there are two pathways that can initiate apoptosis - the intrinsic pathway, which is triggered by internal stimuli like DNA damage, and the extrinsic pathway, which is triggered by external death signals binding to cell surface death receptors. Both pathways ultimately lead to activation of caspases and the execution phase of apoptosis.
How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
-------------------------------------------------------------------------------
Find out more about ISO training and certification services
Training: ISO/IEC 27001 Information Security Management System - EN | PECB
ISO/IEC 42001 Artificial Intelligence Management System - EN | PECB
General Data Protection Regulation (GDPR) - Training Courses - EN | PECB
Webinars: https://pecb.com/webinars
Article: https://pecb.com/article
-------------------------------------------------------------------------------
For more information about PECB:
Website: https://pecb.com/
LinkedIn: https://www.linkedin.com/company/pecb/
Facebook: https://www.facebook.com/PECBInternational/
Slideshare: http://www.slideshare.net/PECBCERTIFICATION
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
1. NUCLEIC ACIDS - STRUCTURE &
FUNCTION
DR. ANU P. ABHIMANNUE,
ASSISTANT PROFESSOR,
DEPARTMENT OF BIOTECHNOLOGY,
ST. MARY’S COLLEGE, THRISSUR
2. DISCOVERY – NUCLEIC ACID
• First observed by Frederich Miescher in 1869.
• The isolated crude extract of DNA & RNA was called nuclein.
• He observed the presence of phosphorus and nitrogen, but not sulfur.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
2
13 August 1844 – 26 August 1895; Swiss
physician and biologist.
3. Researchers – Structure of DNA
• In 1953, James Watson, Francis Crick, Maurice Wilkins and Rosalind Franklin
figured out the structure of DNA.
• Watson, Crick and Wilkins were awarded the Nobel Prize in Medicine in 1962.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
3
James Watson: (born April 6, 1928)
American molecular biologist,
geneticist and zoologist
Francis Crick: (8 June 1916 – 28 July 2004), British
molecular biologist, biophysicist, and
neuroscientist.
Maurice Wilkins: (15 Dec 1916
– 5 Oct 2004), New Zealand-
born British physicist &
molecular biologist
Rosalind Elsie Franklin:
25 July 1920 – 16 April
1958, English chemist &
X-ray crystallographer
4. The most important photo ever taken?
• Photo 51 – Taken by Rosalind
Franklin and Ray Gosling in the
Biophysics Department in 1952.
• This image gave final clue that
enabled others to put together
research from previous two
decades and understand that DNA
was a double helix.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 4
6. STRUCTURE
• Double helix
• 1 complete turn = 34 A°
• Distance between 2 nucleotides = 3.4 A°
• DNA makes a complete turn every 10 residues
• Width of double helix = 20 A°
• Has a minor and major groove (spaces between adjacent turns)
• Runs anti parallel, 5´ 3´ & 3´ 5´
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
6
7. DNA - COMPONETS
• Nucleotide is the building block of DNA.
Nucleoside vs. Nucleotide. A nucleoside consists of a nitrogenous base and sugar
but without the phosphate group. A nucleotide consists of a nitrogenous base, a
sugar (ribose or deoxyribose) and one to three phosphate groups.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
7
8. NUCLEOTIDE
1. 5 carbon sugar – deoxy ribose
2. Phosphate esterified at 5´ position
of sugar ring
3. Nitrogen base at 1´ site.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 8
10. PHOSPHATE GROUP
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 10
• Sugar and phosphate group link by
phosphodiester bond.
• sugar – phosphate - sugar – phosphate
backbone is located outside the molecule
with 2 sets of bases projecting towards the
center.
• Phosphate gives a net negative charge to
DNA molecule
11. CHEMICAL BONDS
• Ester bond between phosphate and 5′OH of deoxyribose sugar.
• Diester bond between 5′phosphate of one nucleotide to
3′carbon of deoxyribose sugar of next nucleotide.
• Glycosidic bond between deoxyribose sugar at its 1st carbon
and nitrogenous Base.
• Double or triple hydrogen bond between nitrogenous bases.
• The A-T pair forms two hydrogen bonds and C-G pair forms
three.
• Hydrogen bonds can be easily disrupted and permits
the strands to separate for transcription and replication.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 11
12. NITROGEN BASES : 2 TYPES
PURINES PYRIMIDINES
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 12
• Double ring structure
• Heterocyclic aromatic organic compound
• Consists of a pyrimidine ring fused to an
imidazole ring.
• IUPAC Name = 9H-purine.
• Chemical formula = C5H4N4
• Aromatic heterocyclic organic compound.
• Six-membered single ring with two nitrogen
atoms at 1 and 3 (positions).
• IUPAC Name = Pyrimidine.
• Chemical formula = C4H4N2.
13. COMPLEMENTARY BASE PAIRING
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
13
• Purine always pairs with pyrimidine and vice versa
• Adenine pairs with Thymine & Guanine pairs with Cytosine
Information about base composition was provided by Erwin
Chargaff.
First parity rule : %A = %T and %G = %C.
Second parity rule: Ratio [C + G] / [A + T] was typically less than
the unity with [C + G] is less abundant.
Chargaff: 11 August 1905 – 20 June
2002; Austro-Hungarian biochemist
14. FUNCTIONS
• Storage of genetic information
• Replication and inheritance
• Expression of genetic message
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
14
16. COMPONENTS
• Ribonucleic acid (RNA) is comparatively shorter and are single
stranded.
• A ribonucleotide in the RNA chain contains
• Ribose (Pentose Sugar)
• Nitrogenous Bases (A, U, G, And C)
• Phosphate Group.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
16
17. Thymidine is replaced by URACIL in RNA
• Aromatic heterocyclic organic
compound.
• Six-membered single ring with
two nitrogen atoms at 1 and 3
(positions).
• IUPAC Name = Pyrimidine.
• Chemical formula = C4H4N2.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 17
18. 3D STRUCTURE
• Even though RNA is single
stranded, most types of RNA
molecules show extensive intra-
molecular base pairing creating a
three-dimensional structure.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 18
19. MODIFIED BASES
• The bases and attached sugars in RNA can be modified in numerous
ways as the RNAs mature.
• Pseudouridine (Ψ) - the linkage between uracil and ribose is changed from a
C–N bond to a C–C bond
• Ribothymidine (T) - 5-methyluridine abbreviated as m5U
• Hypoxanthine – has a deaminated adenine base whose nucleoside is
called inosine (I).
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
19
20. RNA – CLASSIFICATION
Briefly classified into:
• Coding-RNA
• Non-coding RNA (ncRNA)
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
20
21. CODING RNA
• Coding RNA is messenger RNA (mRNA).
• The genetic code from DNA is transformed as the coding sequence of
the mRNA to carry out protein synthesis.
• Immature eukaryotic mRNA is “precursor mRNA (pre-mRNA)” which
later process into mature mRNA.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
21
23. NON CODING RNA
• Ribosomal RNA (rRNA)
• Transfer RNA (tRNA)
• Small nuclear RNAs (snRNA)
• Small nucleolar RNAs (snoRNA)
• MicroRNAs (miRNA)
• Long noncoding RNAs (lncRNA)
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
23
24. Ribosomal RNA (rRNA)
• rRNA is the catalytic component of the ribosomes that are basically
nucleoprotein complex.
• Constitutes 80% of total RNA
• DNA encoding rRNA is present as tandem repeats and is called rDNA.
• The part of chromatin containing rDNA is called nucleolar organizer.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
24
25. STRUCTURE - rRNA
• Undergoes secondary folding and produce a sphere like structure
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
25
27. FUNCTION
• Contains ribozymes (28 S rRNA in eukaryotes and 23 S rRNA in
prokaryotes)
• Ribozymes catalyse synthesis of peptide bond between amino acids.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
27
28. TRANSFER RNA
• 10-15% of total RNA
• Family of 60 small sized (75-93 nucleotides long) RNA
• It has 3ˊOH & 5ˊmonophosphate group
• Also known as soluble, supernatant or adaptor RNA
• Undergoes secondary and tertiary folding
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
28
29. STRUCTURE
• Holley described the structure of
alanine transfer RNA in 1964
• Inspired by Holley’s discovery,
other scientists proved the
structure to be of clover leaf model
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 29
Robert William Holley (January 28, 1922 – February 11,
1993), American biochemist. Nobel Prize in Physiology
or Medicine in 1968
30. The structure of tRNA resembles clover leaf and
hence known as Clover Leaf Model
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 30
31. Amino acid/acceptor arm
• Contains both 5ˊ and 3 ˊ end
• Unpaired end of the arm has CCA always with –
OH at the tip
• -COOH group of amino acid pairs with –OH group
of adenosine base of CCA, in presence of ATP
forming amino acyl tRNA
• Hence, 3 ˊ end is called carrier end
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 31
32. TΨC ARM
• Site for attachment of ribosome
• 5 base pairs in the stem
• 7 nitrogenous bases in the loop
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 32
33. VARIABLE ARM
• Most variable tRNA
• Classified into class I and class II
• Class I – comprise 75% and has 3-5 bp
• Class II – 13-20 bp long
• Generally, 4 -21 nucleotides
• Function not known
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 33
34. ANTI – CODON ARM
• Opposite to amino acid arm
• Loop contains 7 to 11 unpaired nitrogenous
bases
• 3 bases are complementary to codons on
mRNA molecule and known as wobble base
• Terminal end is known as recognition end.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 34
35. D ARM
• Has enzyme recognition site that binds
specific amino acid activating enzyme which
catalyses the union of specific amino acid to
tRNA molecules.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 35
36. FUNCTION
• Key role in protein synthesis. Pick up specific amino acid from
cytoplasm and deliver it to the site of protein synthesis. Attach to
ribosome in accordance with the sequence specified by mRNA.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
36
37. Small nuclear RNAs (snRNA)
• Small nuclear RNAs are always associated with a group of specific proteins to
form the complexes referred to as “small nuclear ribonucleoproteins (snRNP)”
in the nucleus. Their primary function is to process the precursor mRNA (pre-
mRNA).
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
37
38. Small nucleolar RNAs (snoRNA)
• Small nucleolar RNAs are components of small nucleolar
ribonucleoproteins (snoRNPs), which are complexes that are
responsible for sequence-specific nucleotide modification.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
38
39. MicroRNAs (miRNA)
• MicroRNAs are small ncRNAs of ~22 nucleotides.
• Mediate post-transcriptional gene silencing through RNA interference (RNAi), where
an effector complex of miRNA and enzymes can target complementary mRNA by
blocking the mRNA from being translated or accelerating its degradation.
• In human, miRNAs are estimated to regulate the translation of >60% of protein-
coding genes.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
39
40. Long noncoding RNAs (lncRNA)
• Long noncoding RNAs are a heterogeneous group of non-coding
transcripts larger than 200 nt in size and make up the largest portion
of the mammalian non-coding transcriptome.
• lncRNAs are essential in many physiological processes.
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR.
40
41. REFERENCES
• Gerald Karp (2010). Cell and molecular biology: concepts and
experiments (6th ed.). John Wiley & sons. ISBN-13 978-0-470-48337-4.
• https://www.livescience.com/37247-dna.html
• https://www.bbc.com/news/health-18041884
• http://molecularwiki.blogspot.com/2016/08/nucleotides.html
• https://openstax.org/books/microbiology/pages/10-3-structure-and-
function-of-rna
DR ANU P. A., ST. MARY'S COLLEGE, THRISSUR. 41