DNA replication involves the synthesis of new DNA strands through a semi-conservative process whereby each new molecule contains one old strand and one new strand synthesized using the old strand as a template. Key enzymes involved include helicase, which unwinds the DNA double helix, primase, which initiates DNA synthesis, and DNA polymerase, which catalyzes phosphodiester bond formation to elongate the new strands. Fidelity is maintained through proofreading mechanisms that remove incorrectly incorporated nucleotides and DNA repair pathways that correct errors made during replication.
SOS response was discovered by Miroslav Radman. It's a part of DNA repair system- synthesizes enzymes required for DNA repair. Cellular response to UV damage.
SOS response was discovered by Miroslav Radman. It's a part of DNA repair system- synthesizes enzymes required for DNA repair. Cellular response to UV damage.
Basics of Undergraduate/university fellows
Transcription is more complicated in eukaryotes than in prokaryotes because
eukaryotes possess three different classes of RNA polymerases and because of the
way in which transcripts are processed to their functional forms.
More proteins and transcription factors are involved in eukaryotic transcription.
Replication Introduction , DNA replicating Models , Meselson and Stahl Experiments , Circuler Model of DNA replication , Replication in Prokaryotes , Replication In Eukaryotes , Comparison Between Prokaryotes and Eukaryotes Replicaton and PCR (Polymerease Chain Reaction)
Basics of Undergraduate/university fellows
Transcription is more complicated in eukaryotes than in prokaryotes because
eukaryotes possess three different classes of RNA polymerases and because of the
way in which transcripts are processed to their functional forms.
More proteins and transcription factors are involved in eukaryotic transcription.
Replication Introduction , DNA replicating Models , Meselson and Stahl Experiments , Circuler Model of DNA replication , Replication in Prokaryotes , Replication In Eukaryotes , Comparison Between Prokaryotes and Eukaryotes Replicaton and PCR (Polymerease Chain Reaction)
This about the DNA and mechanism of DNA replication. DNA IS A BLUE PRINT OF LIFE.DNA is a major store of genetic information.Located in nucleus and mitochondria.
DNA replication is the process by which DNA makes a copy of itself during cell division.The separation of the two single strands of DNA creates a 'Y' shape called a replication 'fork'. The two separated strands will act as templates for making the new strands of DNA.
“This structure has novel features which are of considerable biological interest.”
This may be the science most famous statement, which appeared in April 1953 in the scientific paper where James Watson and Francis Crick presented the structure of the DNA-helix.
“It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material."
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.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
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!
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
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
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?
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
1. Fidelity of DNA replication
INDRANI KAR
M.Sc Microbiology
St. George College of Management & Science
Bengaluru North University
2. Introduction
• The metabolism of DNA is the chemistry of joining one nucleotides to the next in the
process called DNA replication, is elegant and simple.
• The metabolism of DNA or the DNA replication needs high accuracy that is arrived
by enzymes complexity.
• The enzymes that synthesize DNA molecules are very well known for their ability in
each work in replication, and it may attribute the copies of millions of bases.
• It has done by extraordinary fidelity and speed with the formation of
phosphodiester bonds in proper manner.
3.
4. History of replication
• Watson and Crick proposed the hypothesis of the DNA replication by the model of semi-
conservative model of replication.
• Each DNA strands serves as the template strands for synthesis of a new strand, producing
two new DNA molecules, each with new strand and one old strand. This is semi-
conservative replication.
• After the promising hypothesis of semi-conservative replication, in 1957 Meselson and
stahl grew E. coli cells for generation in the medium in which the sole nitrogen source
NH4CL containing heavy and light isotopes of nitrogen.
• They proved that it is DNA replication is a semi conservative mode of replication , the
DNA possess a new daughter strand and a old mother strand.
5.
6. Enzymes for replication
• Single stranded binding protein or enzyme.
• Helicase enzyme.
• Primase enzyme.
• DNA polymerase III
• DNA polymerase I
• DNA ligase
• DNA gyrase (DNA topoisomerase II)
• Dam methylase enzyme
7.
8. Proteins for replication
• DnaA protein
• DnaB protein
• HU (Histone like bacterial protein)
• FIS ( factor for inversions stimulation )
• IHF (integration host factor)
• DnaG protein
9. Initiation of DNA replication
• The E.coli replication origin oriC , consists of 245 bp and contains DNA sequence
elements that are highly conserved among replication origins.
• DNA first unwinds at the position of A=T base pairs called the DNA unwinding
element.
• DNA unwinds by the DNA unwinding protein or DnaA , DnaB , DnaC and these
three proteins are called helicase enzyme.
• When DNA unwinds the single stranded binding protein stabilized the unwind
DNA single strand.
11. Elongating of replication
• The elongation phase of replication includes two distinct but related operations by
adding same nucleotides.
• At first the primase enzymes add small small nucleotides at the two strands, it only
synthesize the small fragments like 9 to 10.
• When the small fragments are replicated by primase then the polymerase III replicates
long nucleotides by forming the okazaki fragments
• Okazaki fragments leading to the synthesis of two strands leading strand and lagging
strand as in the oposite strand.
• The processivity of DNA replication is done by topoisomerase enzymes.
12.
13.
14. Termination of replication
• Eventually the two replication fork of the circular chromosome meet at the
termination region.
• The termination region containing 20 bp sequence called Ter sequence.
• The tar region arranged on the chromosome to create a trap that a replication fork,
the ter sequence function as binding sites for the protein tus.
• The tus-ter complex can arrest the replication fork from one direction.
• The replication fork encounters a function tus-ter complex, it halts, and other halts
when it meets the first fork.
• Separation of DNA strands are done by topoisomerase, the two daughter strand or
cells segregated by cell division.
16. Fidelity of DNA replication
• Fidelity of DNA replication is depend on the enzyme to catalyze many
reactions before relasing its substrate is called processivity.
• The key of processivity of DNA polymerase that act at the replication
fork in their association with proteins called sliding DNA clamps.
• The speed of DNA synthesis is largely due to the progressive nature of
DNA polymerase III due to it binds with sliding DNA clamps and stabilizes
itself in elongation process.
• Thus the replication fidelity increases.
17.
18. Continue......
• The another reason for fidelity is the proof reading process of replication.
• In proof reading process, the incorrect base pairs remove by the nucleus that originally
identified in the same polypeptide as the DNA polymerase.
• In the polymerase 1 two nuclease , one is exonuclease and one is endonuclease.
• The two nuclease form a functional large fragments called klenow fragment, retains the
polymerization and proof reading activity.
• Thus the fidelity is increased of the DNA replication.
20. CONCLUSION
• DNA replication itself can occasionally damage, called mutation that introduces
error, hence the maintainance of the DNA replication is needed for the next
generation purpose.
• DNA molecules are themselves irreplaceable, it can cause cellular damage too.
• Fidelity of DNA replication depends on the proof reading, repair system as well
as in some enzyme 's function.
• Such mechanism of DNA replication fidelity is also depends on the onway repair
system like nick translation done by the phosphodiester bonds and with the help
of ATPs.