RNA- A polymer of ribonucleotides, is a single stranded structure. There are three major types of RNA- m RNA,t RNA and r RNA. Besides that there are small nuclear,micro RNAs, small interfering and heterogeneous RNAs. Each of them has a specific structure and performs a specific function.
DNA replication is the process by which a cell makes an identical copy of its DNA. It involves unwinding the double helix at an origin of replication and using each parental strand as a template to synthesize new daughter strands. This results in two identical copies of the DNA molecule. Replication is semi-conservative, meaning each new DNA molecule contains one original parental strand and one newly synthesized strand. It is also bidirectional and semi-discontinuous. The leading strand is copied continuously while the lagging strand is copied discontinuously in fragments that are later joined.
The genetic code is a set of rules that specifies how sequences of nucleotides in DNA and RNA correspond to sequences of amino acids in proteins. It defines codons, which are triplets of nucleotides that encode for specific amino acids or start and stop signals. The genetic code is nearly universal across all living organisms and is non-overlapping and triplet-based. It exhibits some level of degeneracy, where more than one codon can encode for the same amino acid. Mutations in the genetic code can lead to changes in the amino acid sequence of proteins and cause disease.
Meselson and Stahl conducted an experiment using E. coli bacteria to test the hypothesis that DNA replicates semi-conservatively. They grew the bacteria in medium containing a heavy isotope of nitrogen, then switched the bacteria to medium with a light isotope. Analysis of DNA densities over multiple generations provided evidence that DNA replication results in one old strand and one new strand in each daughter molecule, supporting the semi-conservative model.
This document discusses transcription in eukaryotes. It begins with definitions of transcription and describes the basic process of RNA being synthesized from a DNA template. It then covers the mechanisms of transcription, including initiation involving RNA polymerase and transcription factors, elongation, and termination. The key similarities between prokaryotic and eukaryotic transcription are that DNA acts as a template and RNA polymerase facilitates RNA synthesis. Key differences are that eukaryotic transcription occurs in the nucleus, is carried out by three classes of RNA polymerase, and RNAs are processed in the nucleus rather than the cytoplasm.
DNA is a double-stranded molecule that forms a helical structure. It is composed of nucleotides, each containing a phosphate group, deoxyribose sugar, and a nitrogenous base. There are two types of bases: purines (adenine and guanine) and pyrimidines (cytosine and thymine). The bases form rungs that link the strands via hydrogen bonds between adenine-thymine and guanine-cytosine. DNA exists in three primary structures - A-DNA, B-DNA, and Z-DNA - which differ in their helical geometry and handedness. The main role of DNA is long-term information storage in the genome that is used for building and maintaining
RNA is one of the major biological macromolecules essential for life. It has several types that serve different functions. Messenger RNA (mRNA) carries genetic information from DNA to the ribosomes for protein synthesis. Ribosomal RNA (rRNA) is the catalytic component of ribosomes and is involved in protein translation. Transfer RNA (tRNA) transfers specific amino acids to the growing polypeptide chain during translation.
The document discusses different forms of DNA structure that can be adopted based on environmental conditions. The main forms discussed are B-DNA, A-DNA, Z-DNA, C-DNA, D-DNA and E-DNA. B-DNA is the most common form, having a right-handed double helix structure with 10 base pairs per turn. A-DNA and Z-DNA are also double helical but have different structural characteristics than B-DNA such as base pair spacing and groove size. The various forms arise in response to changes in humidity, ionic conditions and DNA sequence composition.
DNA replication in prokaryotes involves initiation, elongation, and termination phases. Initiation begins with the binding of initiator proteins to the origin of replication, unwinding the DNA helix to form replication forks. Elongation synthesizes the leading and lagging strands bidirectionally away from the origin using DNA polymerases. Termination occurs when the replication forks meet, completing duplication of the chromosome.
DNA replication is the process by which a cell makes an identical copy of its DNA. It involves unwinding the double helix at an origin of replication and using each parental strand as a template to synthesize new daughter strands. This results in two identical copies of the DNA molecule. Replication is semi-conservative, meaning each new DNA molecule contains one original parental strand and one newly synthesized strand. It is also bidirectional and semi-discontinuous. The leading strand is copied continuously while the lagging strand is copied discontinuously in fragments that are later joined.
The genetic code is a set of rules that specifies how sequences of nucleotides in DNA and RNA correspond to sequences of amino acids in proteins. It defines codons, which are triplets of nucleotides that encode for specific amino acids or start and stop signals. The genetic code is nearly universal across all living organisms and is non-overlapping and triplet-based. It exhibits some level of degeneracy, where more than one codon can encode for the same amino acid. Mutations in the genetic code can lead to changes in the amino acid sequence of proteins and cause disease.
Meselson and Stahl conducted an experiment using E. coli bacteria to test the hypothesis that DNA replicates semi-conservatively. They grew the bacteria in medium containing a heavy isotope of nitrogen, then switched the bacteria to medium with a light isotope. Analysis of DNA densities over multiple generations provided evidence that DNA replication results in one old strand and one new strand in each daughter molecule, supporting the semi-conservative model.
This document discusses transcription in eukaryotes. It begins with definitions of transcription and describes the basic process of RNA being synthesized from a DNA template. It then covers the mechanisms of transcription, including initiation involving RNA polymerase and transcription factors, elongation, and termination. The key similarities between prokaryotic and eukaryotic transcription are that DNA acts as a template and RNA polymerase facilitates RNA synthesis. Key differences are that eukaryotic transcription occurs in the nucleus, is carried out by three classes of RNA polymerase, and RNAs are processed in the nucleus rather than the cytoplasm.
DNA is a double-stranded molecule that forms a helical structure. It is composed of nucleotides, each containing a phosphate group, deoxyribose sugar, and a nitrogenous base. There are two types of bases: purines (adenine and guanine) and pyrimidines (cytosine and thymine). The bases form rungs that link the strands via hydrogen bonds between adenine-thymine and guanine-cytosine. DNA exists in three primary structures - A-DNA, B-DNA, and Z-DNA - which differ in their helical geometry and handedness. The main role of DNA is long-term information storage in the genome that is used for building and maintaining
RNA is one of the major biological macromolecules essential for life. It has several types that serve different functions. Messenger RNA (mRNA) carries genetic information from DNA to the ribosomes for protein synthesis. Ribosomal RNA (rRNA) is the catalytic component of ribosomes and is involved in protein translation. Transfer RNA (tRNA) transfers specific amino acids to the growing polypeptide chain during translation.
The document discusses different forms of DNA structure that can be adopted based on environmental conditions. The main forms discussed are B-DNA, A-DNA, Z-DNA, C-DNA, D-DNA and E-DNA. B-DNA is the most common form, having a right-handed double helix structure with 10 base pairs per turn. A-DNA and Z-DNA are also double helical but have different structural characteristics than B-DNA such as base pair spacing and groove size. The various forms arise in response to changes in humidity, ionic conditions and DNA sequence composition.
DNA replication in prokaryotes involves initiation, elongation, and termination phases. Initiation begins with the binding of initiator proteins to the origin of replication, unwinding the DNA helix to form replication forks. Elongation synthesizes the leading and lagging strands bidirectionally away from the origin using DNA polymerases. Termination occurs when the replication forks meet, completing duplication of the chromosome.
RNA is a polymer made of nucleotides composed of a ribose sugar, phosphate, and one of four nitrogenous bases. It plays essential roles in coding, decoding, regulating, and expressing genes. There are three main types of RNA: ribosomal RNA (rRNA), transfer RNA (tRNA), and messenger RNA (mRNA). rRNA makes up 85% of total cellular RNA and forms the ribosome. tRNA transfers amino acids to the ribosome during protein synthesis according to mRNA codons. mRNA carries coding sequences from DNA to be translated into proteins.
DNA is a double-helix molecule that carries genetic instructions. It is composed of two strands of polynucleotides made up of nucleotides, each containing a nitrogenous base, sugar, and phosphate. The strands are stabilized by hydrogen bonds between complementary bases and base-stacking interactions. DNA can be denatured into single strands by elevated temperature, extreme pH, low salt concentrations, or chemicals that disrupt hydrogen bonding between strands. Denaturation temperature depends on factors like base composition and length. Renaturation occurs when double-stranded DNA is cooled under conditions that allow the strands to re-form hydrogen bonds and complementary base pairing.
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.
The document discusses the wobble hypothesis proposed by Francis Crick in 1966. The hypothesis explains how a single tRNA molecule can recognize multiple codons for an amino acid by allowing non-canonical "wobble" base pairing between the third base of the codon and first base of the tRNA anticodon. This wobble pairing means that more codons exist than the number of tRNA molecules, resolving the degeneracy of the genetic code. The relaxed base pairing rules at the third position of the codon-anticodon duplex are significant as they allow for broader tRNA specificity while maintaining thermodynamic stability.
The document discusses the three main types of RNA: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries copies of instructions from DNA to the ribosome and acts as a messenger between DNA and protein synthesis. rRNA combines with proteins to form ribosomes, which are the sites of protein synthesis. tRNA transfers amino acids to the growing polypeptide chain during protein translation and acts as an adapter between mRNA and amino acids.
tRNA is a small RNA molecule that helps deliver amino acids to the ribosome during protein synthesis. It has a cloverleaf secondary structure with four stems and loops that allows it to bind to both an amino acid and mRNA. The anticodon loop binds to mRNA through base pairing with codons, while the acceptor stem binds to an amino acid via an ester bond formed by the amino acid and the 3' end of tRNA. tRNA undergoes extensive processing and modification after transcription to achieve its mature L-shaped tertiary structure and perform its role in protein synthesis.
DNA replication is the process by which DNA copies itself in living cells. It occurs in three main steps: initiation, elongation, and termination. Initiation begins at origins of replication, where proteins assemble into pre-replication complexes. During elongation, helicase unwinds the DNA strands and DNA polymerase adds complementary nucleotides to each strand. Termination occurs when the replication forks meet, with telomerase ensuring complete replication of chromosome ends.
Post-transcriptional modifications help process primary transcripts into mRNA in three main ways: 1) 5' capping protects the transcript and aids export from the nucleus, 2) Polyadenylation aids stability and transport, and 3) Splicing removes introns and ligates exons to form mature mRNA. In eukaryotes, this occurs in the nucleus and is essential for efficient translation. It can also result in alternative splicing to increase protein diversity from a single gene.
This document discusses the different levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure refers to the amino acid sequence. Secondary structure includes alpha helices, beta sheets, and beta turns formed by hydrogen bonding between amino acids. Tertiary structure is the 3D conformation determined by interactions between side chains. Quaternary structure refers to the arrangement of multiple polypeptide subunits in multimeric proteins. The structures are determined through techniques like X-ray crystallography and NMR.
The document summarizes the structure of DNA. It describes that DNA is composed of four nucleotides - adenine, guanine, cytosine, and thymine. These nucleotides are linked by phosphodiester bonds to form a double helix structure. The bases pair with each other according to Watson-Crick base pairing rules - adenine pairs with thymine and guanine pairs with cytosine. Hydrogen bonds stabilize the pairing between the bases. The double helix structure has an antiparallel arrangement with the strands running in opposite directions.
This document summarizes the process of translation. Translation is the process by which the sequence of nucleotides in messenger RNA directs the incorporation of amino acids into a protein. It involves three main steps - initiation, elongation, and termination. Initiation requires various initiation factors and ribosomal subunits to form the initiation complex. Elongation is a cyclic process of aminoacyl-tRNA binding, peptide bond formation, and translocation. Termination occurs when a stop codon is reached, releasing the polypeptide chain. Ribosomal recycling then dissociates the post-termination complex to prepare the ribosome for another round of translation.
This document discusses post-translational modifications (PTMs), which are enzymatic modifications of proteins after translation. It describes various types of PTMs like trimming, covalent attachments through phosphorylation, glycosylation, sulfation, methylation, and hydroxylation. The importance of PTMs in regulating protein function and cellular processes is highlighted. Detection methods for PTMs like mass spectrometry and fluorescent staining are also mentioned.
The document discusses the structure of proteins at various levels of organization:
- Proteins are composed of amino acids linked together by peptide bonds to form polypeptide chains. The sequence and interactions of these chains determine the protein's structure.
- There are four levels of protein structure - primary, secondary, tertiary, and quaternary. Secondary structure includes alpha helices and beta sheets formed by hydrogen bonding between amino acids in the chain. Tertiary structure describes the overall 3D shape formed by interactions between amino acid side chains. Quaternary structure involves the interaction of multiple polypeptide chains.
- Protein structure enables proteins to perform their diverse functions through processes like enzyme catalysis, oxygen transport, and providing structure
DNA replication is the process by which DNA copies itself. It occurs during cell division and involves unwinding the DNA double helix, synthesizing new strands that are complementary to the original strands, and producing two identical DNA molecules each with one original and one new strand. Key enzymes involved include DNA helicase, DNA primase, DNA polymerases, and DNA ligase which work together to replicate DNA in a semi-conservative manner beginning at origins of replication on the DNA.
This document discusses the structure, properties, and functions of DNA. It describes DNA as a polymer composed of deoxyribonucleotides that carries the genetic information found in chromosomes, mitochondria, and chloroplasts. The basic structure of DNA involves two anti-parallel strands coiled around each other to form the familiar double helix structure, held together by hydrogen bonds between complementary nucleotide base pairs and base stacking interactions. DNA exists in various structural forms and undergoes compaction in the cell, ultimately forming chromatin through association with histone proteins. The primary function of DNA is to serve as the template for its own replication and transcription into RNA to direct protein synthesis.
The genetic code is a dictionary that translates nucleotide sequences into amino acid sequences. It is composed of 64 codons that are read in groups of three nucleotides. The genetic code is universal, unambiguous, redundant, and non-overlapping. It specifies 20 standard amino acids through 61 codons, while 3 codons are stop signals that terminate protein synthesis. The code allows for wobbling in base pairing at the third position of codons, increasing decoding efficiency. Mutations can alter protein sequences through changes to codons.
The genetic code is defined as the sequence of DNA nucleotides that determines the sequence of amino acids in protein synthesis. It is universal across all lifeforms. The genetic code has the following key properties: it is triplet, meaning three nucleotides code for each amino acid; comma-less and non-overlapping, with no breaks or overlaps between codons; non-ambiguous, with each codon coding for only one amino acid; and redundant, with some amino acids coded for by multiple codons. The genetic code is read in the 5' to 3' direction and includes start codons that initiate protein synthesis and stop codons that terminate protein synthesis.
DNA replication is the process by which a cell makes an identical copy of its DNA before cell division. It involves unwinding the DNA double helix at an origin of replication and using each strand as a template to synthesize new partner strands. RNA primers are used to initiate DNA synthesis, which occurs semi-conservatively and bidirectionally from the replication fork to produce two identical copies of the original DNA molecule.
This document provides an overview of gene regulation in prokaryotes using the lac operon in E. coli as an example. It explains that genes are regulated to control which proteins are expressed at different times. The lac operon consists of structural genes that encode enzymes for lactose metabolism, as well as a regulatory gene that produces a repressor protein. In the absence of the lactose inducer, the repressor binds to the operator region and prevents transcription. When lactose is present, it binds to the repressor and causes a conformational change that prevents it from binding to the operator, allowing transcription.
Gene expression in eukaryotes is regulated through multiple mechanisms at the transcriptional and post-transcriptional levels. These mechanisms allow for adaptation, tissue specificity, and development. Regulation occurs through chromatin remodeling, enhancers/repressors, locus control regions, gene amplification, rearrangement, and alternative RNA processing. Key differences between prokaryotic and eukaryotic gene expression include larger eukaryotic genomes, different cell types, lack of operons, chromatin structure, and uncoupled transcription/translation.
Regulated gene expression is required for adaptation, differentiation, and development in organisms. In prokaryotes, genes involved in metabolic pathways are often arranged in operons, where a single regulatory region controls multiple structural genes. The lac operon in E. coli regulates genes for lactose metabolism. In the absence of lactose, the lac repressor binds the operator region and prevents transcription. When lactose is present, it binds the repressor and induces a conformational change that reduces its affinity for DNA, allowing transcription. This is an example of negative regulation through repression and derepression.
RNA is a polymer made of nucleotides composed of a ribose sugar, phosphate, and one of four nitrogenous bases. It plays essential roles in coding, decoding, regulating, and expressing genes. There are three main types of RNA: ribosomal RNA (rRNA), transfer RNA (tRNA), and messenger RNA (mRNA). rRNA makes up 85% of total cellular RNA and forms the ribosome. tRNA transfers amino acids to the ribosome during protein synthesis according to mRNA codons. mRNA carries coding sequences from DNA to be translated into proteins.
DNA is a double-helix molecule that carries genetic instructions. It is composed of two strands of polynucleotides made up of nucleotides, each containing a nitrogenous base, sugar, and phosphate. The strands are stabilized by hydrogen bonds between complementary bases and base-stacking interactions. DNA can be denatured into single strands by elevated temperature, extreme pH, low salt concentrations, or chemicals that disrupt hydrogen bonding between strands. Denaturation temperature depends on factors like base composition and length. Renaturation occurs when double-stranded DNA is cooled under conditions that allow the strands to re-form hydrogen bonds and complementary base pairing.
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.
The document discusses the wobble hypothesis proposed by Francis Crick in 1966. The hypothesis explains how a single tRNA molecule can recognize multiple codons for an amino acid by allowing non-canonical "wobble" base pairing between the third base of the codon and first base of the tRNA anticodon. This wobble pairing means that more codons exist than the number of tRNA molecules, resolving the degeneracy of the genetic code. The relaxed base pairing rules at the third position of the codon-anticodon duplex are significant as they allow for broader tRNA specificity while maintaining thermodynamic stability.
The document discusses the three main types of RNA: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries copies of instructions from DNA to the ribosome and acts as a messenger between DNA and protein synthesis. rRNA combines with proteins to form ribosomes, which are the sites of protein synthesis. tRNA transfers amino acids to the growing polypeptide chain during protein translation and acts as an adapter between mRNA and amino acids.
tRNA is a small RNA molecule that helps deliver amino acids to the ribosome during protein synthesis. It has a cloverleaf secondary structure with four stems and loops that allows it to bind to both an amino acid and mRNA. The anticodon loop binds to mRNA through base pairing with codons, while the acceptor stem binds to an amino acid via an ester bond formed by the amino acid and the 3' end of tRNA. tRNA undergoes extensive processing and modification after transcription to achieve its mature L-shaped tertiary structure and perform its role in protein synthesis.
DNA replication is the process by which DNA copies itself in living cells. It occurs in three main steps: initiation, elongation, and termination. Initiation begins at origins of replication, where proteins assemble into pre-replication complexes. During elongation, helicase unwinds the DNA strands and DNA polymerase adds complementary nucleotides to each strand. Termination occurs when the replication forks meet, with telomerase ensuring complete replication of chromosome ends.
Post-transcriptional modifications help process primary transcripts into mRNA in three main ways: 1) 5' capping protects the transcript and aids export from the nucleus, 2) Polyadenylation aids stability and transport, and 3) Splicing removes introns and ligates exons to form mature mRNA. In eukaryotes, this occurs in the nucleus and is essential for efficient translation. It can also result in alternative splicing to increase protein diversity from a single gene.
This document discusses the different levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure refers to the amino acid sequence. Secondary structure includes alpha helices, beta sheets, and beta turns formed by hydrogen bonding between amino acids. Tertiary structure is the 3D conformation determined by interactions between side chains. Quaternary structure refers to the arrangement of multiple polypeptide subunits in multimeric proteins. The structures are determined through techniques like X-ray crystallography and NMR.
The document summarizes the structure of DNA. It describes that DNA is composed of four nucleotides - adenine, guanine, cytosine, and thymine. These nucleotides are linked by phosphodiester bonds to form a double helix structure. The bases pair with each other according to Watson-Crick base pairing rules - adenine pairs with thymine and guanine pairs with cytosine. Hydrogen bonds stabilize the pairing between the bases. The double helix structure has an antiparallel arrangement with the strands running in opposite directions.
This document summarizes the process of translation. Translation is the process by which the sequence of nucleotides in messenger RNA directs the incorporation of amino acids into a protein. It involves three main steps - initiation, elongation, and termination. Initiation requires various initiation factors and ribosomal subunits to form the initiation complex. Elongation is a cyclic process of aminoacyl-tRNA binding, peptide bond formation, and translocation. Termination occurs when a stop codon is reached, releasing the polypeptide chain. Ribosomal recycling then dissociates the post-termination complex to prepare the ribosome for another round of translation.
This document discusses post-translational modifications (PTMs), which are enzymatic modifications of proteins after translation. It describes various types of PTMs like trimming, covalent attachments through phosphorylation, glycosylation, sulfation, methylation, and hydroxylation. The importance of PTMs in regulating protein function and cellular processes is highlighted. Detection methods for PTMs like mass spectrometry and fluorescent staining are also mentioned.
The document discusses the structure of proteins at various levels of organization:
- Proteins are composed of amino acids linked together by peptide bonds to form polypeptide chains. The sequence and interactions of these chains determine the protein's structure.
- There are four levels of protein structure - primary, secondary, tertiary, and quaternary. Secondary structure includes alpha helices and beta sheets formed by hydrogen bonding between amino acids in the chain. Tertiary structure describes the overall 3D shape formed by interactions between amino acid side chains. Quaternary structure involves the interaction of multiple polypeptide chains.
- Protein structure enables proteins to perform their diverse functions through processes like enzyme catalysis, oxygen transport, and providing structure
DNA replication is the process by which DNA copies itself. It occurs during cell division and involves unwinding the DNA double helix, synthesizing new strands that are complementary to the original strands, and producing two identical DNA molecules each with one original and one new strand. Key enzymes involved include DNA helicase, DNA primase, DNA polymerases, and DNA ligase which work together to replicate DNA in a semi-conservative manner beginning at origins of replication on the DNA.
This document discusses the structure, properties, and functions of DNA. It describes DNA as a polymer composed of deoxyribonucleotides that carries the genetic information found in chromosomes, mitochondria, and chloroplasts. The basic structure of DNA involves two anti-parallel strands coiled around each other to form the familiar double helix structure, held together by hydrogen bonds between complementary nucleotide base pairs and base stacking interactions. DNA exists in various structural forms and undergoes compaction in the cell, ultimately forming chromatin through association with histone proteins. The primary function of DNA is to serve as the template for its own replication and transcription into RNA to direct protein synthesis.
The genetic code is a dictionary that translates nucleotide sequences into amino acid sequences. It is composed of 64 codons that are read in groups of three nucleotides. The genetic code is universal, unambiguous, redundant, and non-overlapping. It specifies 20 standard amino acids through 61 codons, while 3 codons are stop signals that terminate protein synthesis. The code allows for wobbling in base pairing at the third position of codons, increasing decoding efficiency. Mutations can alter protein sequences through changes to codons.
The genetic code is defined as the sequence of DNA nucleotides that determines the sequence of amino acids in protein synthesis. It is universal across all lifeforms. The genetic code has the following key properties: it is triplet, meaning three nucleotides code for each amino acid; comma-less and non-overlapping, with no breaks or overlaps between codons; non-ambiguous, with each codon coding for only one amino acid; and redundant, with some amino acids coded for by multiple codons. The genetic code is read in the 5' to 3' direction and includes start codons that initiate protein synthesis and stop codons that terminate protein synthesis.
DNA replication is the process by which a cell makes an identical copy of its DNA before cell division. It involves unwinding the DNA double helix at an origin of replication and using each strand as a template to synthesize new partner strands. RNA primers are used to initiate DNA synthesis, which occurs semi-conservatively and bidirectionally from the replication fork to produce two identical copies of the original DNA molecule.
This document provides an overview of gene regulation in prokaryotes using the lac operon in E. coli as an example. It explains that genes are regulated to control which proteins are expressed at different times. The lac operon consists of structural genes that encode enzymes for lactose metabolism, as well as a regulatory gene that produces a repressor protein. In the absence of the lactose inducer, the repressor binds to the operator region and prevents transcription. When lactose is present, it binds to the repressor and causes a conformational change that prevents it from binding to the operator, allowing transcription.
Gene expression in eukaryotes is regulated through multiple mechanisms at the transcriptional and post-transcriptional levels. These mechanisms allow for adaptation, tissue specificity, and development. Regulation occurs through chromatin remodeling, enhancers/repressors, locus control regions, gene amplification, rearrangement, and alternative RNA processing. Key differences between prokaryotic and eukaryotic gene expression include larger eukaryotic genomes, different cell types, lack of operons, chromatin structure, and uncoupled transcription/translation.
Regulated gene expression is required for adaptation, differentiation, and development in organisms. In prokaryotes, genes involved in metabolic pathways are often arranged in operons, where a single regulatory region controls multiple structural genes. The lac operon in E. coli regulates genes for lactose metabolism. In the absence of lactose, the lac repressor binds the operator region and prevents transcription. When lactose is present, it binds the repressor and induces a conformational change that reduces its affinity for DNA, allowing transcription. This is an example of negative regulation through repression and derepression.
Transcription II- Post transcriptional modifications and inhibitors of Transc...Namrata Chhabra
This document discusses post-transcriptional modifications of RNA and inhibitors of transcription. It describes how primary transcripts of rRNA, tRNA and mRNA undergo processing in both prokaryotes and eukaryotes. For rRNA, introns are removed and exons are ligated. For tRNA, extra nucleotides are removed, bases are modified and the CCA tail is added. For mRNA, a 5' cap is added, introns are spliced out, a poly-A tail is attached. Splicing produces tissue-specific proteins. Inhibitors like rifampicin, actinomycin D and alpha-amanitin block transcription by binding DNA or RNA polymerase.
The document discusses DNA transcription in prokaryotes and eukaryotes. In prokaryotes, transcription involves initiation at a promoter region, elongation of RNA polymerase along the DNA, and termination. Initiation requires binding of RNA polymerase and sigma factor to the promoter. Elongation follows base pairing rules. Termination can be rho-dependent or independent. Eukaryotic transcription is more complex, occurring in the nucleus with three RNA polymerases and more elaborate promoter and regulatory elements that control transcription.
Gene therapy involves delivering genes to correct genetic abnormalities. The first successful gene therapy treated a girl with severe combined immunodeficiency. Gene therapy can replace, deactivate, introduce, or enhance genes to treat diseases. Viral and non-viral vectors are used to deliver genes. While gene therapy has treated some genetic diseases and cancers, it remains imperfect as many diseases involve multiple genes and genes can be difficult to target precisely without risks.
The document discusses biotransformation and detoxification reactions. It describes how xenobiotics are metabolized in two phases: Phase 1 involves reactions like hydroxylation and Phase 2 involves conjugating these products to make them more hydrophilic and excretable, through glucuronidation, sulfation, acetylation, methylation or conjugation to amino acids or glutathione. The cytochrome P450 system is important for Phase 1 reactions like oxidation. Phase 2 makes compounds more polar through conjugating them to compounds like glucuronic acid. This allows xenobiotics to be safely eliminated from the body.
This document contains a biochemistry quiz with multiple choice and short answer questions testing various concepts. Over 40 questions are presented across topics including enzyme reactions, protein synthesis, laboratory techniques, disease identification, biochemical structures and processes, and metabolic pathways. For each question, the corresponding answer is provided. The quiz covers foundational biochemistry content for medical students.
Mechanism of action of enzymes- By Hurnaum Karishma (Student SSR Medical Coll...Namrata Chhabra
The document summarizes various mechanisms by which enzymes catalyze biochemical reactions. It discusses how enzymes lower the activation energy of reactions by providing alternative transition states through covalent catalysis, acid-base catalysis, catalysis by bond strain, and catalysis by proximity and orientation of substrates. It also explains how enzymes remain unchanged after reactions and greatly increase reaction rates by enhancing the formation of products from substrates.
Biological oxidation and oxidative phosphorylationNamrata Chhabra
The document discusses cellular respiration and the electron transport chain. It states that organisms extract energy through respiration from organic molecules. During respiration, electrons are released from oxidation reactions and shuttled by electron carriers like NAD+ to the electron transport chain, where the electron energy is converted to ATP. The electron transport chain consists of four complexes embedded in the mitochondrial inner membrane that sequentially transfer electrons from NADH and FADH2 to oxygen to generate a proton gradient for ATP synthesis.
This document summarizes several lipid storage diseases: Tay Sachs disease results from hexosaminidase A deficiency leading to ganglioside accumulation and is classified based on neurological symptom onset. Gaucher disease stems from glucocerebrosidase deficiency causing glucosylceramide storage in reticuloendothelial cells. Niemann Pick disease types A and B involve sphingomyelin accumulation in the liver, spleen, and bone marrow due to different enzymes. Several other diseases are mentioned that involve deficiencies in enzymes responsible for degrading specific lipids.
Glucose tolerance test- Indications, contraindications, preparation of a patient, precautions, types of GTT, normal curve, diabetic curve, renal glycosuria, lag curve, Criteria for diagnosis of DM
This document discusses glucose homeostasis and the maintenance of blood glucose levels. It explains that glucose homeostasis relies on a balance between glucose production in the liver and uptake by tissues. Insulin is a key regulator that promotes glucose uptake after meals and inhibits production during fasting. Other hormones like glucagon stimulate production when glucose levels drop. The document outlines the complex mechanisms that keep blood glucose within a narrow range to ensure the brain has a continuous supply while allowing for variations from meals and activity.
Obesity- Metabolic alterations, complications and treatmentNamrata Chhabra
The document discusses complications and treatment of obesity. It summarizes that obesity affects almost all systems of the body and is associated with various comorbidities related to cardiology, dermatology, endocrinology, gastrointestinal, neurology, oncology, metabolism, and psychology. The prognosis of obesity is usually poor, increasing risks of various diseases. Obesity can be treated through diet, physical exercise, behavioral modification, medications, and bariatric surgery.
The document discusses lipids and fatty acids. It defines lipids as a heterogeneous group of compounds related more by physical than chemical properties, that are relatively insoluble in water but soluble in nonpolar solvents. Fatty acids are aliphatic carboxylic acids that occur mainly as esters in natural fats and oils. They can be classified as saturated or unsaturated based on whether they contain double bonds. Common saturated fatty acids include palmitic acid and stearic acid, while monounsaturated fatty acids include oleic acid. Polyunsaturated fatty acids contain two or more double bonds and important examples are linoleic acid and alpha-linolenic acid.
This document summarizes the three main types of RNA - messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA) - and their roles in protein synthesis. It also briefly discusses the history of RNA discovery, including the discoveries of tRNA, rRNA, and catalytic RNA (ribozymes). Key events included Friedrich Miescher's discovery of nucleic acids in 1868, Severo Ochoa's discovery of how RNA is synthesized winning him the 1959 Nobel Prize, and Robert Holley's determination of the first tRNA sequence winning him the 1968 Nobel Prize.
The document summarizes key aspects of sulfur-containing amino acid metabolism. It discusses how methionine is converted to cysteine and cystine and its role in transmethylation reactions through the intermediate S-adenosylmethionine (SAM). SAM transfers methyl groups to various acceptors and is converted to S-adenosylhomocysteine. Homocysteine can then be remethylated to regenerate methionine or condensed with serine to form cystathionine for cysteine synthesis. Transmethylation reactions are important for activating many compounds and regulating protein turnover through methylation. Causes of hypermethioninemia include impaired utilization, excessive remethylation, and hepatic dysfunction.
Metabolism of Sulfur Containing Amino Acids (Methionine, Cysteine, Cystine)Ashok Katta
Methionine and cysteine are sulfur-containing amino acids involved in important metabolic pathways.
Methionine is an essential amino acid that is converted to S-adenosylmethionine (SAM), which acts as a methyl group donor in transmethylation reactions. SAM is also regenerated back to methionine. Cysteine is synthesized from methionine and serine via cystathionine. It can be catabolized through transamination or direct oxidation pathways.
Genetic disorders of methionine and cysteine metabolism include cystinuria, cystinosis, hypermethioninemia, and different types of homocystinurias caused by defects in enzymes involved in
- Methionine and cysteine are sulfur-containing amino acids. Methionine is an essential amino acid while cysteine can be synthesized from methionine and serine.
- There are three major metabolic routes for methionine and cysteine: 1) methionine is used for transmethylation, 2) methionine is used for cysteine synthesis, and 3) cysteine is broken down to make specialized products.
- Deficiencies in enzymes involved in methionine and cysteine metabolism can cause inborn errors such as homocystinuria, cystathioninuria, and cystinosis.
RNA has several types that perform different functions in the cell. Messenger RNA (mRNA) carries genetic information from DNA to the ribosomes for protein synthesis. Transfer RNA (tRNA) transfers amino acids to the ribosome during protein synthesis by binding to mRNA codons through complementary base pairing. Ribosomal RNA (rRNA) is the major constituent of ribosomes and plays key roles in protein synthesis such as catalyzing peptide bond formation. The different RNA types have distinct structures that enable their functions.
RNA and DNA are nucleic acids that differ in their chemical structure and functions. RNA is typically single-stranded and can form hairpin loops, while DNA is double-stranded. There are various types of RNA that serve different cellular roles. Messenger RNA (mRNA) carries genetic information from DNA to the ribosomes for protein synthesis. Transfer RNA (tRNA) transports amino acids to the ribosome during protein assembly according to the mRNA sequence. Ribosomal RNA (rRNA) is a core component of ribosomes and plays a key role in protein translation.
This document discusses various types of RNA. There are three main classes of RNA - messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). mRNA carries coding information from DNA to the ribosome for protein synthesis. tRNA transfers amino acids to the ribosome during protein synthesis. rRNA is a core component of ribosomes and plays a key role in protein synthesis. The document also describes other RNA types including microRNAs, small nuclear RNAs, and heterogeneous nuclear RNA involved in processing mRNA.
RNA is a ribonucleic acid that helps in the synthesis of proteins in our body. This nucleic acid is responsible for the production of new cells in the human body. It is usually obtained from the DNA molecule.
RNA exists in various forms that perform important cellular functions. The major types of RNA include messenger RNA (mRNA), which carries genetic information from DNA to direct protein synthesis, transfer RNA (tRNA) that transports amino acids, and ribosomal RNA (rRNA) which combines with proteins to form ribosomes and facilitate protein synthesis. Other RNAs include small nuclear RNAs that process mRNA, microRNAs and small interfering RNAs that regulate gene expression, and heterogeneous nuclear RNA that is processed into mRNA.
RNA exists in several forms that are involved in protein synthesis and regulation. Major RNA types include messenger RNA (mRNA), which carries genetic code from DNA to ribosomes for protein production. Ribosomal RNA (rRNA) is a core component of ribosomes where protein synthesis occurs. Transfer RNA (tRNA) transports amino acids to the ribosome during protein assembly. Small nuclear RNAs (snRNAs) help process mRNA, while microRNAs (miRNAs) and small interfering RNAs (siRNAs) regulate gene expression. Certain RNA molecules function as catalysts in cells. New research indicates miRNAs and siRNAs could be targeted for therapeutic drug development.
RNA differs from DNA in several key ways. RNA is typically single-stranded, contains ribose sugar instead of deoxyribose, and contains uracil instead of thymine. There are multiple types of RNA that serve different cellular functions, including messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). mRNA carries coding information from DNA to the ribosome for protein synthesis. tRNA transfers amino acids to the ribosome during protein assembly according to the mRNA codon sequence. rRNA is a core component of ribosomes and facilitates protein translation.
RNA is a polymer of ribonucleotides linked together by phosphodiester linkages. It exists primarily as messenger RNA, transfer RNA, and ribosomal RNA. Messenger RNA carries coding information from DNA to the ribosome. Transfer RNA transfers amino acids to the ribosome during protein synthesis according to the mRNA codon sequence. Ribosomal RNA is the main catalytic component of ribosomes, where protein synthesis occurs. RNA differs from DNA in having ribose rather than deoxyribose, uracil rather than thymine, and secondary structures. Non-coding RNAs like microRNAs and small interfering RNAs also play important gene regulatory roles.
types and structure of prokaryotic RNATooba Kanwal
RNA exists in different single-stranded structures that are involved in protein synthesis or regulation. Messenger RNA (mRNA) carries genetic information from DNA to the ribosome. Ribosomal RNA (rRNA) is a component of ribosomes and facilitates protein translation. Transfer RNA (tRNA) transports amino acids to the ribosome and translates mRNA codons into amino acids during protein synthesis.
1. The document outlines the structure and function of nucleic acids DNA and RNA.
2. Key points covered include the central dogma of molecular biology, the Watson-Crick structure of DNA, types of RNA like mRNA, tRNA and rRNA, and their roles in gene expression and protein synthesis.
3. The document also discusses properties of nucleic acids like denaturation and reannealing of DNA as well as unique features of eukaryotic mRNA.
Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation, and expression of genes. RNA and DNA are nucleic acids, and, along with proteins and carbohydrates, constitute the four major macromolecules essential for all known forms of life. Like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA it is more often found in nature as a single-strand folded onto itself, rather than a paired double-strand.
This document discusses DNA structure and replication. It begins by describing the structure of DNA as a double helix with two antiparallel strands held together by hydrogen bonds between complementary nucleotide base pairs. DNA replication is then summarized as a semi-conservative process where the parental DNA strands separate and each acts as a template for new complementary strands to be synthesized, resulting in two new DNA molecules each with one original and one new strand. The key steps of replication including initiation, unwinding of the strands, primer formation, elongation of new strands, and ligation are also outlined.
RNA is present in all living cells and comes in various types. It is found in both the cytoplasm and nucleus of cells. Messenger RNA (mRNA) carries genetic information from DNA and is involved in protein synthesis. Transfer RNA (tRNA) acts as an intermediary between mRNA and amino acids during protein synthesis. Ribosomal RNA (rRNA) is the most abundant type and forms the major structural component of ribosomes. Different RNA types have distinct structures and functions important for protein synthesis and genetic inheritance in cells.
This document discusses RNA structure and function. It begins by outlining the central dogma of molecular biology - DNA to mRNA to protein. It then notes that the human genome contains around 10,000 protein-coding genes, and that most mRNAs contain untranslated regions and introns. The rest of the document compares and contrasts the key structural differences between RNA and DNA, discusses various RNA structural motifs, and provides examples of specific RNA structures and their functions.
The document discusses nucleic acids and RNA. It defines nucleic acids as macromolecules composed of nucleotide chains, with each nucleotide containing a nitrogenous base, pentose sugar, and phosphate group. RNA is described as a type of nucleic acid that contains ribose rather than deoxyribose and uracil instead of thymine. The document outlines the three main types of RNA - messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA) - and their roles in protein synthesis.
RNA plays important roles in coding, decoding, regulating, and expressing genes. The three main types of RNA are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). mRNA comprises 5% of cellular RNA and carries coding information from DNA to sites of protein synthesis. tRNA transports amino acids to ribosomes and ensures the correct amino acid is added through complementary base pairing. rRNA makes up 80% of cellular RNA and is a major component of ribosomes, facilitating protein synthesis.
This document provides information about RNA and different types of RNA. It discusses that RNA, like DNA, is composed of nucleotides joined by phosphodiester bonds, but contains ribose instead of deoxyribose and uracil instead of thymine. There are two main types of RNA - genetic RNA that acts as the genetic material of some viruses, and non-genetic RNA involved in protein synthesis, including messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). The document describes the structure and functions of mRNA and tRNA in protein synthesis.
RNA.- a short view into sturcture and function of RNAharitha shankar
1. RNA is an important nucleic acid found in most prokaryotic and eukaryotic cells in addition to DNA. Some viruses contain only RNA, which acts as their genetic material.
2. There are two main types of RNA - genetic RNA found in viruses, and non-genetic RNA which depends on DNA for synthesis. Non-genetic RNA includes messenger RNA, ribosomal RNA, and transfer RNA.
3. Messenger RNA carries genetic information from DNA to ribosomes for protein synthesis. It has a 5' cap, coding region, and 3' poly-A tail. Ribosomal RNA forms the major structural component of ribosomes. Transfer RNA transfers amino acids to the ribosome during protein
RNA has several types that serve different functions:
- Messenger RNA (mRNA) carries genetic information from DNA in the nucleus to the ribosome where protein is synthesized. It is single-stranded and contains a 5' cap and 3' poly-A tail.
- Transfer RNA (tRNA) transports specific amino acids to the ribosome and pairs them with mRNA codons during protein translation. It has a cloverleaf secondary structure.
- Ribosomal RNA (rRNA) is a major component of ribosomes and facilitates protein synthesis by providing the structural scaffold for the ribosome.
Similar to RNA- Structure, Types and Functions (20)
Recombinant DNA technology allows for the creation of novel gene combinations not found in nature. Genes can be inserted into host cells and replicated. This technology is used in research, medicine, agriculture, and industry. In medicine, it enables production of insulin, growth factors, vaccines, and gene therapy. It is also used for genetic mapping, disease diagnosis, forensics, and prenatal testing. In agriculture, it improves crop yields and develops pest/drought resistance. Industry utilizes it to produce enzymes, additives, sugars, and chemicals.
Recombinant DNA technology involves manipulating DNA sequences in the laboratory. DNA is isolated, cut with restriction enzymes, and joined with DNA ligase. The recombinant DNA is inserted into a cloning vector and introduced into a host cell. Cells containing the recombinant DNA are selected and amplified. This allows large quantities of identical DNA molecules to be produced for analysis, comparison, and other purposes. Common applications include understanding disease, producing therapeutic proteins, disease prevention through vaccines, diagnosis, and gene therapy.
Polymerase Chain Reaction- Principle, procedure, and applications of PCRNamrata Chhabra
The document discusses various topics including education, healthcare, transportation, communication technologies, food production, lifestyle, and environmental protection. It suggests that over the next 30 years, many areas will experience significant changes and advancements due to emerging technologies such as artificial intelligence, robotics, and renewable energy sources which will transform our lives.
The document discusses 16 clinical case studies presented by Dr. Namrata Chhabra involving patients' medical histories, laboratory results, and biochemical abnormalities. For each case, Dr. Chhabra asks students to provide diagnoses based on the evidence and explain the underlying biochemical defects or mechanisms. The cases cover topics like diabetes, acid-base imbalances, enzyme deficiencies, and vitamin deficiency disorders.
Selenium- chemistry, functions and clinical significanceNamrata Chhabra
1. Selenium is an essential trace element that functions in the body as part of selenoproteins but can be toxic at high levels.
2. A misformulated liquid dietary supplement resulted in 201 cases of selenium poisoning due to the selenium concentration being approximately 200 times the labeled amount.
3. Symptoms of selenium toxicity included hair loss, nail discoloration, and worsening of gastrointestinal symptoms.
Copper- sources, daily requirement, absorption, transportation, storage, excretion, role in enzymatic action, role in iron metabolism, role in elastin maturation, role in bone formation, copper deficiency, copper toxicity, Wilson disease, Menkes disease.
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Sugar derivatives and reactions of monosaccharidesNamrata Chhabra
Reactions of monosaccharides, osazone formation, reduction, oxidation, reaction with acids and alkalies, ester formation and formation of amino sugars, amino sugar acids and deoxy sugars.
This document discusses isomers of monosaccharides. It begins by classifying monosaccharides based on number of carbon atoms (trioses, tetroses, pentoses, hexoses). It then discusses different types of isomers that can occur in monosaccharides: epimers arising from differences in hydroxyl group position; anomers arising from ring opening/closing; D/L isomers arising from asymmetric carbon configuration; and aldose-ketose isomers arising from functional group differences. Specific examples like glucose, fructose and their isomers are provided. Structural representations like Fischer projections, Haworth projections and chair/boat conformations are also explained.
Definition of ELISA, Immunochemical principle of ELISA, Direct, Indirect, Sandwich and Competitive ELISA, applications of ELISA in the diagnostic field, and benefits/drawbacks of ELISA.
An 80-year-old man presented with symptoms of Alzheimer's disease including memory loss, disorientation, difficulty completing tasks, and mood changes. Brain scans and examination of brain tissue confirmed Alzheimer's disease. Alzheimer's is caused by abnormal accumulation of tau and amyloid-beta proteins in the brain, which form plaques and tangles that damage neurons. It is diagnosed based on symptoms, cognitive tests, and brain imaging, and progresses from mild to severe impairment over time. There are medications to temporarily improve symptoms but no cure for the underlying disease process.
Molecular biology revision-Part 3 (Regulation of genes expression and Recombi...Namrata Chhabra
1) Gene expression in eukaryotes is regulated through various mechanisms including chromatin remodeling, enhancers and repressors, locus control regions, gene amplification, gene rearrangement, alternative RNA processing, class switching, and mRNA stability.
2) Key differences in prokaryotic and eukaryotic gene expression include larger eukaryotic genomes, different cell types requiring gene regulation, lack of operons, chromatin structure, and uncoupling of transcription and translation.
3) The lac operon in E. coli is regulated through negative control in the absence of lactose, double negative control in the presence of only lactose, and absence of positive control in the presence of both glucose and lactose.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
Leveraging Generative AI to Drive Nonprofit InnovationTechSoup
In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
Beyond Degrees - Empowering the Workforce in the Context of Skills-First.pptxEduSkills OECD
Iván Bornacelly, Policy Analyst at the OECD Centre for Skills, OECD, presents at the webinar 'Tackling job market gaps with a skills-first approach' on 12 June 2024
Philippine Edukasyong Pantahanan at Pangkabuhayan (EPP) CurriculumMJDuyan
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 𝟏)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐄𝐏𝐏 𝐂𝐮𝐫𝐫𝐢𝐜𝐮𝐥𝐮𝐦 𝐢𝐧 𝐭𝐡𝐞 𝐏𝐡𝐢𝐥𝐢𝐩𝐩𝐢𝐧𝐞𝐬:
- Understand the goals and objectives of the Edukasyong Pantahanan at Pangkabuhayan (EPP) curriculum, recognizing its importance in fostering practical life skills and values among students. Students will also be able to identify the key components and subjects covered, such as agriculture, home economics, industrial arts, and information and communication technology.
𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐍𝐚𝐭𝐮𝐫𝐞 𝐚𝐧𝐝 𝐒𝐜𝐨𝐩𝐞 𝐨𝐟 𝐚𝐧 𝐄𝐧𝐭𝐫𝐞𝐩𝐫𝐞𝐧𝐞𝐮𝐫:
-Define entrepreneurship, distinguishing it from general business activities by emphasizing its focus on innovation, risk-taking, and value creation. Students will describe the characteristics and traits of successful entrepreneurs, including their roles and responsibilities, and discuss the broader economic and social impacts of entrepreneurial activities on both local and global scales.
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4. Differences between RNA and DNA
S.No. RNA DNA
1) Single stranded mainly except Double stranded (Except for
when self complementary certain viral DNA s which are
sequences are there it forms a single stranded)
double stranded structure (Hair
pin structure)
2) Ribose is the main sugar The sugar moiety is deoxy
ribose
3) Pyrimidine components differ. Thymine is always there but
Thymine is never found(Except uracil is never found
tRNA)
4) Being single stranded structure- It does follow Chargaff's rule.
It does not follow Chargaff’s rule The total purine content in a
double stranded DNA is always
equal to pyrimidine content.
Biochemistry For Medics 4
5. Differences between RNA and DNA
S.No. RNA DNA
5) RNA can be easily destroyed by DNA resists alkali action due to
alkalies to cyclic diesters of the absence of OH group at 2’
mono nucleotides. position
6) RNA is a relatively a labile DNA is a stable molecule. The
molecule, undergoes easy and spontaneous degradation is
spontaneous degradation very 2 slow. The genetic
information can be stored for
years together without any
change.
7) Mainly cytoplasmic, but also Mainly found in nucleus, extra
present in nucleus (primary nuclear DNA is found in
transcript and small nuclear mitochondria, and plasmids
RNA) etc
8) The base content varies from Millions of base pairs are there
100- 5000. The size is variable. depending upon the organism
Biochemistry For Medics 5
6. Differences between RNA and DNA
S.No. RNA DNA
9) There are various types of RNA – DNA is always of one type and
mRNA, r RNA, t RNA, Sn RNA, Si performs the function of
RNA, mi RNA and hn RNA. These storage and transfer of genetic
RNAs perform different and information.
specific functions.
10) No variable physiological forms There are variable forms of
of RNA are found. The different DNA (A to E and Z)
types of RNA do not change
their forms
11) RNA is synthesized from DNA, it DNA can form DNA by
can not form DNA(except by the replication, it can also form
action of reverse transcriptase). RNA by transcription.
It can not duplicate (except in
certain viruses where it is a
genomic material )
12) Many copies of RNA are present Single copy of DNA is present
per cell per cell.
Biochemistry For Medics 6
7. Types of RNA
In all prokaryotic and eukaryotic
organisms, three main classes of RNA
molecules exist-
1) Messenger RNA(m RNA)
2) Transfer RNA (t RNA)
3) Ribosomal RNA (r RNA)
The other are –
o small nuclear RNA (SnRNA),
o micro RNA(mi RNA) and
o small interfering RNA(Si RNA) and
o heterogeneous nuclear RNA (hnRNA).
Biochemistry For Medics 7
8. Messenger RNA (m-RNA)
Comprises only 5% of the RNA in the cell
Most heterogeneous in size and base sequence
All members of the class function as
messengers carrying the information in a gene to
the protein synthesizing machinery
Biochemistry For Medics 8
9. Structural Characteristics of
m-RNA
The 5’ terminal end is capped by 7-
methyl guanosine triphosphate cap.
The cap is involved in the
recognition of mRNA by the
translating machinery
It stabilizes m RNA by protecting it
from 5’ exonuclease
Biochemistry For Medics 9
10. Structural Characteristics of
m-RNA(contd.)
The 3’end of most m-RNAs have a polymer of
Adenylate residues( 20-250)
The tail prevents the attack by 3’ exonucleases
Histones and interferons do not contain poly A
tails
On both 5’ and 3’ end there are non coding
sequences which are not translated (NCS)
The intervening region between non coding
sequences present between 5’ and 3’ end is
called coding region. This region encodes for the
synthesis of a protein.
Biochemistry For Medics 10
12. Structural Characteristics of
m-RNA(Contd.)
The m- RNA molecules are formed with the help of
DNA template during the process of transcription.
The sequence of nucleotides in m RNA is
complementary to the sequence of nucleotides on
template DNA.
The sequence carried on m -RNA is read in the form
of codons.
A codon is made up of 3 nucleotides
The m-RNA is formed after processing of
heterogeneous nuclear RNA
Biochemistry For Medics 12
13. Heterogeneous nuclear RNA
(hnRNA)
In mammalian nuclei , hnRNA is the
immediate product of gene transcription
The nuclear product is heterogeneous in size
(Variable) and is very large.
Molecular weight may be more than 107, while
the molecular weight of m RNA is less than 2x 106
75 % of hnRNA is degraded in the nucleus,
only 25% is processed to mature
m RNA
Biochemistry For Medics 13
14. Heterogeneous nuclear RNA
(hnRNA)
Mature m –RNA is formed from primary transcript by
capping, tailing, splicing and base modification.
Biochemistry For Medics 14
15. Transfer RNA (t- RNA)
Transfer RNA are the smallest of three major species of
RNA molecules
They have 74-95 nucleotide residues
They are synthesized by the nuclear processing of a
precursor molecule
They transfer the amino acids from cytoplasm to the
protein synthesizing machinery, hence the name t RNA.
They are easily soluble , hence called “Soluble RNA or s
RNA
They are also called Adapter molecules, since they act as
adapters for the translation of the sequence of nucleotides
of the m RNA in to specific amino acids
There are at least 20 species of t RNA one corresponding
to each of the 20 amino acids required for protein
synthesis.
Biochemistry For Medics 15
16. Structural characteristics of t- RNA
1) Primary structure- The nucleotide
sequence of all the t RNA molecules allows
extensive intrastand complimentarity that
generates a secondary structure.
2) Secondary structure- Each single t- RNA
shows extensive internal base pairing and
acquires a clover leaf like structure. The
structure is stabilized by hydrogen bonding
between the bases and is a consistent
feature.
Biochemistry For Medics 16
17. Structural characteristics of t-
RNA
Secondary structure (Clover leaf structure)
All t-RNA contain 5 main arms or loops
which are as follows-
a) Acceptor arm
b) Anticodon arm
c) D HU arm
d) TΨ C arm
e) Extra arm
Biochemistry For Medics 17
18. Secondary structure of t- RNA
a)Acceptor arm
The acceptor arm is at 3’ end
It has 7 base pairs
The end sequence is unpaired
Cytosine, Cytosine-Adenine at the 3’ end
The 3’ OH group terminal of Adenine binds with
carboxyl group of amino acids
The t RNA bound with amino acid is called
Amino acyl t RNA
CCA attachment is done post transcriptionally
Biochemistry For Medics 18
19. Secondary structure of t- RNA
The carboxyl group of amino acid is attached to 3’OH group of Adenine
nucleotide of the acceptor arm. The anticodon arm base pairs with the codon
present on the m- RNA
Biochemistry For Medics 19
20. Secondary structure of t-
RNA(contd.)
b) Anticodon arm
Lies at the opposite end of acceptor arm
5 base pairs long
Recognizes the triplet codon present in the m
RNA
Base sequence of anticodon arm is
complementary to the base sequence of m RNA
codon.
Due to complimentarity it can bind specifically
with m RNA by hydrogen bonds.
Biochemistry For Medics 20
21. Secondary structure of t-
RNA(contd.)
c) DHU arm
It has 3-4 base pairs
Serves as the recognition site for the enzyme (amino
acyl t RNA synthetase) that adds the amino acid to the
acceptor arm.
d) TΨC arm
This arm is opposite to DHU arm
Since it contains pseudo uridine that is why it is so
named
It is involved in the binding of t RNA to the ribosomes
Biochemistry For Medics 21
22. Secondary structure of t-
RNA(contd.)
e) Extra arm or Variable arm
About 75 % of t RNA molecules possess
a short extra arm
If about 3-5 base pairs are present the
t-RNA is said to be belonging to class 1.
Majority t -RNA belong to class 1.
The t –RNA belonging to class 2 have
long extra arm, 13-21 base pairs in length.
Biochemistry For Medics 22
23. Tertiary structure of t- RNA
The L shaped tertiary
structure is formed by
further folding of the clover
leaf due to hydrogen bonds
between T and D arms.
The base paired double
helical stems get arranged in
to two double helical
columns, continuous and
perpendicular to one
another.
Biochemistry For Medics 23
24. Ribosomal RNA (rRNA)
The mammalian ribosome contains two major
nucleoprotein subunits—a larger one with a molecular
weight of 2.8 x 106 (60S) and a smaller subunit with a
molecular weight of 1.4 x 106 (40S).
The 60S subunit contains a 5S ribosomal RNA (rRNA), a
5.8S rRNA, and a 28S rRNA; there are also probably more
than 50 specific polypeptides.
The 40S subunit is smaller and contains a single 18S
rRNA and approximately 30 distinct polypeptide chains.
All of the ribosomal RNA molecules except the 5S rRNA
are processed from a single 45S precursor RNA molecule
in the nucleolus .
5S rRNA is independently transcribed.
Biochemistry For Medics 24
26. Ribosomal RNA (rRNA)
The functions of the ribosomal RNA
molecules in the ribosomal particle are not
fully understood, but they are necessary for
ribosomal assembly and seem to play key
roles in the binding of mRNA to ribosomes
and its translation
Recent studies suggest that an rRNA
component performs the peptidyl transferase
activity and thus is an enzyme (a ribozyme).
Biochemistry For Medics 26
27. Small RNA
Most of these molecules are
complexed with proteins to form
ribonucleoproteins and are distributed in
the nucleus, in the cytoplasm, or in both.
They range in size from 20 to 300
nucleotides and are present in 100,000–
1,000,000 copies per cell.
Biochemistry For Medics 27
28. Small Nuclear RNAs (snRNAs)
snRNAs, a subset of the small RNAs, are
significantly involved in mRNA processing and
gene regulation
Of the several snRNAs, U1, U2, U4, U5, and
U6 are involved in intron removal and the
processing of hnRNA into mRNA
The U7 snRNA is involved in production of
the correct 3' ends of histone mRNA—which
lacks a poly(A) tail.
Biochemistry For Medics 28
29. Small Nuclear RNAs (snRNAs).
Sn RNA s are involved in the process of splicing (intron removal) of primary
transcript to form mature m RNA. The Sn RNA s form complexes with proteins
to form Ribonucleoprotein particles called snRNPs
Biochemistry For Medics 29
30. Micro RNAs, miRNAs, and Small
Interfering RNAs, siRNAs
These two classes of RNAs represent a
subset of small RNAs; both play important
roles in gene regulation.
miRNAs and siRNAs cause inhibition of
gene expression by decreasing specific
protein production albeit apparently via
distinct mechanisms
Biochemistry For Medics 30
31. Micro RNAs (miRNAs)
miRNAs are typically 21–25 nucleotides in
length and are generated by nucleolytic
processing of the products of distinct
genes/transcription units
The small processed mature miRNAs
typically hybridize, via the formation of
imperfect RNA-RNA duplexes within the 3'-
untranslated regions of specific target
mRNAs, leading via unknown mechanisms to
translation arrest.
Biochemistry For Medics 31
32. Micro RNAs (miRNAs)
microRNAs, short non-coding RNAs present in all living organisms, have
been shown to regulate the expression of at least half of all human
genes. These single-stranded RNAs exert their regulatory action by
binding messenger RNAs and preventing their translation into
proteins.
Biochemistry For Medics 32
33. Small Interfering RNAs (siRNAs)
siRNAs are derived by the specific nucleolytic cleavage
of larger, double-stranded RNAs to again form small 21–
25 nucleotide-long products.
These short siRNAs usually form perfect RNA-RNA
hybrids with their distinct targets potentially anywhere
within the length of the mRNA where the complementary
sequence exists.
Formation of such RNA-RNA duplexes between siRNA
and mRNA results in reduced specific protein production
because the siRNA-mRNA complexes are degraded by
dedicated nucleolytic machinery;
some or all of this mRNA degradation occurs in specific
organelles termed P bodies.
Biochemistry For Medics 33
34. Small Interfering RNAs (siRNAs)
Small interfering RNA (siRNA) are 20-25 nucleotide-long double-stranded RNA
molecules that have a variety of roles in the cell. They are involved in the RNA
interference (RNAi) pathway, where it interferes with the expression of a
specific gene by hybridizing to its corresponding RNA sequence in the
target mRNA. This then activates the degrading mRNA. Once the target
mRNA is degraded, the mRNA cannot be translated into protein.
Biochemistry For Medics 34
35. Significance of mi RNAs and si
RNAs
Both miRNAs and siRNAs represent
exciting new potential targets for
therapeutic drug development in humans.
In addition, siRNAs are frequently used to
decrease or "knock-down" specific protein
levels in experimental procedures in the
laboratory, an extremely useful and
powerful alternative to gene-knockout
technology.
Biochemistry For Medics 35
36. Summary
RNA exists in several different single-stranded
structures, most of which are directly or indirectly
involved in protein synthesis or its regulation.
The linear array of nucleotides in RNA consists of A, G,
C, and U, and the sugar moiety is ribose.
The major forms of RNA include messenger RNA
(mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA),
and small nuclear RNAs (snRNAs; miRNAs).
Certain RNA molecules act as catalysts (ribozymes).
miRNAs and siRNAs represent exciting new potential
targets for therapeutic drug development in humans.
Biochemistry For Medics 36