The document describes the lac operon in E. coli, which regulates genes involved in lactose metabolism. The lac operon contains three structural genes - lacZ, lacY, and lacA - that are regulated by the lac repressor and catabolite activator protein (CAP). The lac repressor normally binds to the operator region and blocks transcription. In the presence of lactose, allolactose binds to the lac repressor and causes it to detach from DNA. CAP promotes transcription when glucose levels are low, allowing the cell to preferentially metabolize lactose over glucose. Together, these regulatory mechanisms ensure the lac genes are only expressed when lactose is available and glucose is not.
INTERFERENCE means the act of interfering with something, here, with RNA. RNAi is an evolutionarily conserved mechanism triggered by dsRNA molecules, to prevent the expression of specific genes or the translation, causes sequence-specific degradation of the targeted mRNA molecules of that particular gene. It was also known as CO-SUPPRESSION, POST TRANSCRIPTIONAL GENE SILENCING [PTGS] in plants and QUELLING in fungi.
INTERFERENCE means the act of interfering with something, here, with RNA. RNAi is an evolutionarily conserved mechanism triggered by dsRNA molecules, to prevent the expression of specific genes or the translation, causes sequence-specific degradation of the targeted mRNA molecules of that particular gene. It was also known as CO-SUPPRESSION, POST TRANSCRIPTIONAL GENE SILENCING [PTGS] in plants and QUELLING in fungi.
Hello everyone, I am Dr. Ujwalkumar Trivedi, Head of Biotechnology Department at Marwadi University Rajkot. I teach Molecular Biology to the students of M.Sc. Microbiology and Biotechnology.
The current presentation describes various co-transcriptional and post-transcriptional RNA modifications in eukaryotic cells. The following processes are described in detail:
1. 5' mRNA Capping
2. Splicing
3. Alternative Splicing
4. 3' Polyadenylation
5. RNA Editing
Enjoy Reading.
Regulation of gene expression in eukaryotesAnna Purna
Presence of nucleus and complexity of eukaryotic organism demands a well controlled gene regulation in eukaryotic cell. Tissue specific gene expression is essential as they are multicellular organisms in which different cells perform different functions. This PPT deals with various control points for the gene regulation and expression within a cell.
Gene regulation can be defined as any kind of alteration in the gene to give rise to a different expression which might result in a change in the synthesized amino acid sequence.”
Gene expression is basically the synthesis of the polypeptide chain encoded by a particular gene.
Therefore the expression of the gene can be quantified in terms of the amount of protein synthesised by the genes.
The presentation covers the details of DNA replication starting from the basics of the replication process to the chemistry of DNA synthesis as well as the different models of replication.
I have described in this presentation the critical points in the maturation of small non-coding RNA especially miRNA and its role in the development and diagnosis of specific psychiatric disorders
The control of gene expression or protein synthesis is called gene regulation or it is the process of turning genes on and off
Gene regulation in prokaryotes is most extensively observed at the initiation of transcription.
Most genes are controlled by extracellular signals- present in medium.
Repressor, a negative regulatory molecule, binds to the operator gene and interferes with the expression of genes. Activator, a positive regulatory molecule, enhances the expression of the genes.
Operon : a group or cluster of structural genes under a single promoter; bacterial operons are polycistronic transcripts that are able to produce multiple proteins from one mRNA
Francois Jacob and Jacques Monod in 1961
“Lac operon is an operon or a group of genes with a single promoter that encode genes for the transport and metabolism of lactose in E.coli and other bacteria.”
Lac operon concept is an example of prokaryotic gene regulation.
Hello everyone, I am Dr. Ujwalkumar Trivedi, Head of Biotechnology Department at Marwadi University Rajkot. I teach Molecular Biology to the students of M.Sc. Microbiology and Biotechnology.
The current presentation describes various co-transcriptional and post-transcriptional RNA modifications in eukaryotic cells. The following processes are described in detail:
1. 5' mRNA Capping
2. Splicing
3. Alternative Splicing
4. 3' Polyadenylation
5. RNA Editing
Enjoy Reading.
Regulation of gene expression in eukaryotesAnna Purna
Presence of nucleus and complexity of eukaryotic organism demands a well controlled gene regulation in eukaryotic cell. Tissue specific gene expression is essential as they are multicellular organisms in which different cells perform different functions. This PPT deals with various control points for the gene regulation and expression within a cell.
Gene regulation can be defined as any kind of alteration in the gene to give rise to a different expression which might result in a change in the synthesized amino acid sequence.”
Gene expression is basically the synthesis of the polypeptide chain encoded by a particular gene.
Therefore the expression of the gene can be quantified in terms of the amount of protein synthesised by the genes.
The presentation covers the details of DNA replication starting from the basics of the replication process to the chemistry of DNA synthesis as well as the different models of replication.
I have described in this presentation the critical points in the maturation of small non-coding RNA especially miRNA and its role in the development and diagnosis of specific psychiatric disorders
The control of gene expression or protein synthesis is called gene regulation or it is the process of turning genes on and off
Gene regulation in prokaryotes is most extensively observed at the initiation of transcription.
Most genes are controlled by extracellular signals- present in medium.
Repressor, a negative regulatory molecule, binds to the operator gene and interferes with the expression of genes. Activator, a positive regulatory molecule, enhances the expression of the genes.
Operon : a group or cluster of structural genes under a single promoter; bacterial operons are polycistronic transcripts that are able to produce multiple proteins from one mRNA
Francois Jacob and Jacques Monod in 1961
“Lac operon is an operon or a group of genes with a single promoter that encode genes for the transport and metabolism of lactose in E.coli and other bacteria.”
Lac operon concept is an example of prokaryotic gene regulation.
Includes definition, discovery.Enzyme induction is a process in which a molecule (e.g., a drug) induces (i.e., initiates or enhances) the expression of an enzyme.
The induction of heat shock proteins in the fruit fly Drosophila melanogaster.
The Lac operon is an interesting example of how gene expression can be regulated.
Viruses, despite having only a few genes, possess mechanisms to regulate their gene expression, typically into an early and late phase, using collinear systems regulated by anti-terminators (lambda phage) or splicing modulators (HIV).
Gal4 is a transcriptional activator that controls the expression of GAL1, GAL7, and GAL10 (all of which code for the metabolic of galactose in yeast). The GAL4/UAS system has been used in a variety of organisms across various phyla to study gene expression.
Transcription and the control of gene expression [Autosaved].pptxAbdullahAli647576
The first genetic maps, constructed in the organisms
such as the fruit fly, used genes as markers.
• The only genes that could be studied were those
specifying phenotypes that were distinguishable by
visual examination. Eg. Eye color, height.
• Some organisms have very few visual characteristics
so gene mapping with these organisms has to rely on
biochemical phenotypes
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
1. Y4E01-BASIC MOLECULAR
BIOLOGY
Dr. s. sivasankara narayani
Assistant professor
Department of Microbiology
Ayya nadar Janaki ammal college
sivakasi
12-01-2021Dr.SS ., MRSB (UK)
2. UNIT - I
• Nucleic acid: DNA as the genetic material – direct and indirect
evidences. RNA as the genetic material. Structure, types and
properties of DNA and RNA. Chargaff’s rule. Genetic code:
Properties – codon - anticodon - *Wobble hypothesis. Law of DNA
constancy and C-value paradox.
12-01-2021Dr.SS ., MRSB (UK)
3. UNIT - II
• DNA replication: Theories - rolling circle mechanism –
semiconservative - conservative and discontinuous- evidences.
Enzymes involved in replication of DNA in prokaryotes and
eukaryotes.
12-01-2021Dr.SS ., MRSB (UK)
4. UNIT - III
• Transcription process in prokaryotes and eukaryotes: Initiation -
elongation - termination. RNA processing in eukaryotes: Capping -
polyadenylation - *splicing. Translation in prokaryotes and
eukaryotes: Initiation - elongation - termination. Post translational
modification in eukaryotes.
12-01-2021Dr.SS ., MRSB (UK)
5. UNIT - IV
Regulation of gene expression in bacterial system : Operon concept
– lac, trp, ara operon in E. coli - *DNA methylation and
heterochromatization. Transposons (brief account only).
12-01-2021Dr.SS ., MRSB (UK)
6. UNIT- V
Mutation : Types - molecular basis of spontaneous and induced
mutations. Mutagenic agents: Chemical and physical mutagens.
Isolation of auxotrophs and drug resistance mutant. Toxicity testing-
*Ames test. DNA damage and repair (photoreactivation, excision).
12-01-2021Dr.SS ., MRSB (UK)
7. LAC OPERON
• The lac operon of E. coli contains genes involved in lactose metabolism. It's expressed
only when lactose is present and glucose is absent.
• Two regulators turn the operon "on" and "off" in response to lactose and glucose levels:
the lac repressor and catabolite activator protein (CAP).
• The lac repressor acts as a lactose sensor. It normally blocks transcription of the operon,
but stops acting as a repressor when lactose is present. The lac repressor senses lactose
indirectly, through its isomer allolactose.
• Catabolite activator protein (CAP) acts as a glucose sensor. It activates transcription of
the operon, but only when glucose levels are low. CAP senses glucose indirectly, through
the "hunger signal" molecule cAMP.
12-01-2021Dr.SS ., MRSB (UK)
8. OPERON
• Operon is operating units which can be defined as the cluster of
genes located together on the chromosomes & transcribed
together.
• It is group of closely linked structure genes & associated control
gene which regulate the metabolic activity.
• All the genes of an operon are coordinately controlled by a
mechanism 1st described in 1961 by Francois Jacob & Jaques Monod
of the Pasture institute of Paris.
12-01-2021Dr.SS ., MRSB (UK)
9. LAC OPERON
• The lactose operon designated as lac operon.
• The lac operon codes for enzymes involved in the catabolism
(degradation) of lactose.
• lactose is the disaccharide which is made up of glucose &
galactose.
• It is the inducible operon since the presence of lactose induce the
operon to switched on.
12-01-2021Dr.SS ., MRSB (UK)
10. STRUCTURE
• The lac operon contains three genes: lacZ, lacY, and lacA. These genes are
transcribed as a single mRNA, under control of one promoter.
• Genes in the lac operon specify proteins that help the cell utilize lactose.
• lacZ encodes an enzyme that splits lactose into monosaccharides (single-unit sugars)
that can be fed into glycolysis.
• Similarly, lacY encodes a membrane-embedded transporter that helps bring lactose
into the cell.
• In addition to the three genes, the lac operon also contains a number of regulatory
DNA sequences. These are regions of DNA to which particular regulatory proteins
can bind, controlling transcription of the operon.
12-01-2021Dr.SS ., MRSB (UK)
11. . Structural genes of lac operon:
• lac Z codes for the enzyme β-galactosidase, a tetramer of about 500 kD.
• This enzyme breaks down β-galactoside into its monosaccharide components.
For example, lactose is split into glucose and galactose which can be
metabolized further through glycolysis.
ii. lac Y codes for the β-galactoside permease, a 30 kD membrane-bound protein
which transports β-galactosides into the cell.
iii. lac A codes for β-galactoside transacetylase, that transfers an acetyl group
from acetyl-CoA to β-galactosides (role in lac operon not clear).
12-01-2021Dr.SS ., MRSB (UK)
12. Regulatory genes
• The regulatory genes of lac operon includes promoter gene, operator gene, lac I, and catabolite
activator protein (CAP) binding site.
i. The promoter is the binding site for RNA polymerase, the enzyme that performs transcription.
ii. The operator is a negative regulatory site where the lac repressor protein binds. It is located between
the promoter and the structural genes and overlaps with the promoter.
iii. Lac I (repressor) gene codes for the lac operon repressor, which is a tetramer of identical subunits
of 38 kD each. This gene is located adjacent to the promoter of the lac operon, with its own
promoter and terminator and is always transcribed, hence the repressor is always synthesized.
iv. The repressor is a diffusible product, making Lac I is a trans-acting gene. Repressor binds the operator
to repress (turn off) the operon.
v. Catabolite Activator Protein (CAP) binding site is a positive regulatory site located just upstream of
the lac operon promoter, where the catabolite activator protein (CAP) binds.
vi. The CAP is a dimer protein, which has binding sites for cAMP and DNA. When cAMP binds CAP,
its affinity for the DNA increases. When bound to DNA, CAP promotes transcription by aiding RNA
polymerase bind to the promoter more efficiently.
12-01-2021Dr.SS ., MRSB (UK)
14. LAC OPERON
• The promoter is the binding site for RNA polymerase, the enzyme
that performs transcription.
• The operator is a negative regulatory site bound by
the lac repressor protein. The operator overlaps with the
promoter, and when the lac repressor is bound, RNA polymerase
cannot bind to the promoter and start transcription.
• The CAP binding site is a positive regulatory site that is bound by
catabolite activator protein (CAP). When CAP is bound to this site,
it promotes transcription by helping RNA polymerase bind to the
promoter.
12-01-2021Dr.SS ., MRSB (UK)
15. The lac repressor
• The lac repressor is a protein that represses (inhibits)
transcription of the lac operon. It does this by binding to the
operator, which partially overlaps with the promoter. When bound,
the lac repressor gets in RNA polymerase's way and keeps it from
transcribing the operon.
• When lactose is not available, the lac repressor binds tightly to
the operator, preventing transcription by RNA polymerase.
However, when lactose is present, the lac repressor loses its
ability to bind DNA. It floats off the operator, clearing the way for
RNA polymerase to transcribe the operon.
12-01-2021Dr.SS ., MRSB (UK)
17. …
• This change in the lac repressor is caused by the small
molecule allolactose, an isomer (rearranged version) of lactose.
When lactose is available, some molecules will be converted to
allolactose inside the cell. Allolactose binds to the lac repressor
and makes it change shape so it can no longer bind DNA.
• Allolactose is an example of an inducer, a small molecule that
triggers expression of a gene or operon. The lac operon is
considered an inducible operon because it is usually turned off
(repressed), but can be turned on in the presence of the inducer
allolactose.
12-01-2021Dr.SS ., MRSB (UK)
18. Catabolite activator protein (CAP)
• When lactose is present, the lac repressor loses its DNA-binding ability. This
clears the way for RNA polymerase to bind to the promoter and transcribe
the lac operon. That sounds like the end of the story, right?
• Well...not quite. As it turns out, RNA polymerase alone does not bind very well
to the lac operon promoter. It might make a few transcripts, but it won't do
much more unless it gets extra help from catabolite activator protein (CAP).
CAP binds to a region of DNA just before the lac operon promoter and helps RNA
polymerase attach to the promoter, driving high levels of transcription.
12-01-2021Dr.SS ., MRSB (UK)
20. • CAP isn't always active (able to bind DNA). Instead, it's regulated by a small
molecule called cyclic AMP (cAMP). cAMP is a "hunger signal" made by E.
coli when glucose levels are low. cAMP binds to CAP, changing its shape and
making it able to bind DNA and promote transcription. Without cAMP, CAP
cannot bind DNA and is inactive.
• CAP is only active when glucose levels are low (cAMP levels are high). Thus,
the lac operon can only be transcribed at high levels when glucose is absent.
This strategy ensures that bacteria only turn on the lac operon and start using
lactose after they have used up all of the preferred energy source (glucose).
12-01-2021Dr.SS ., MRSB (UK)