SlideShare a Scribd company logo
ReplicationReplication
Dr Ifat Ara Begum
Associate Professor
Dept of Biochemistry
Dhaka Medical
College Dhaka
1
Structure of DNAStructure of DNA
10/13/18Footer Text 2
10/13/18Footer Text 3
10/13/18Footer Text 4
Chargaff's rule”
A = T & C = G
10/13/18Footer Text 5
What is Replication?What is Replication?
6
 Fundamental process by which cell
copies its DNA to transfer the genetic
information to daughter cells
 DNA directed DNA synthesis
 Base sequence of daughter DNA (newly
synthesized DNA) is identical to the
base sequence of parent DNA
(template).
 The major event in S-phase of cell cycle
10/13/18Footer Text 7
10/13/18Footer Text 8
9
Replication is the
basis for the
biological inheritance
 Precise and
accurate DNA
replication is necessary
to prevent genetic
abnormalities which
often lead to cell death
or disease
 Cell must replicate its DNA before division
 Ultimately, exactly two identical semi-
conserved chromosomes are produced
Function ofFunction of
enzymes/proteinenzymes/protein
Unwinding/melting of
DS DNA in to
single
strand
Prevention of
premature
reassociation /
annealing of
melted DNA
RNA primer synthesis
Catalyzes joining of
nucleotides to 3’-
terminal of the
growing chain
(deoxynucleotides
polymerization)
Sealing the single
strand nick &
connecting okazaki
fragments on
lagging strand
Relieves torsional
strain resulting from
helicase-induced unwinding
Criteria / Features of ReplicationCriteria / Features of Replication
17
 Semi
conservative
process: 50% of
parental DNA is
conserved in
each of daughter
DNA
 Symmetric process: After
unwinding of DS DNA, each of
the 2 single stranded parental
DNA serves as template for
synthesis of new
complementary daughter DNA
 Copying of template always occurs from 3’ to 5’
direction & synthesis of new strand from 5’ to 3’
direction
 Needs primer
18
 Bidirectional
process: From a
specific ORI,
replication
proceeds in both
direction
 Process of high fidelity : As
DNAP has proof reading
property, replication is a
process of high fidelity &
there is no need of post
replicational modification
 Non selective process: The whole genome is
copied
 Semi discontinuous process: B/w two strands,
one replicates continuously without interruption
whereas the other one replicated discontinuously
with interruption.
Semi discontinuous DNA ReplicationSemi discontinuous DNA Replication
Energy of replicationEnergy of replication
21
 The nucleotides used for replication
arrives as nucleoside tri phosphate
i.e.
the bases are with their own energy
source for bonding
10/13/18Footer Text 22
Some
related
topics
10/13/18Footer Text 23
1. DNA Polymerase
TYPE FUNCTION
DNAP-α  Initiation of DNA synthesis
 Synthesis of primer
DNAP-β  Excision of primer
 DNA repair
DNAP-γ Mitochondrial DNA replication
with proof reading
DNAP-δ Synthesis of lagging strand with
proof reading
DNAP-ε  Synthesis of leading strand
with proof reading
 DNA repair
10/13/18Footer Text 28
2. Origin Of
Replication (ORI)
10/13/18Footer Text 33
3. Replicon
34
Functional unit of
replication
Replicated region of DNA centering a
definite ORI
Or
Space between 2 adjacent origins
Each replicon has
origin, terminus
and control
elements of
replication
10/13/18Footer Text 35
4. Replication bubble
&
Replication fork
36
10/13/18Footer Text 39
5. Topological crisis
40
41
 Topological crisis is created when
melting of DS DNA applies turning
force creating positive super coiling
forward to the unmelted DNA double
helix.
 It tends to cause cessation of further
DNA separation due to torsional
strain.
 Topoisomerase relieves the torsional
strain resulting from helicase-induced
unwinding
10/13/18Footer Text 42
6. RNA Primer
10/13/18Footer Text 44
7. Leading strand &
Lagging strand
45
 In replication, both the strands of DNA
acts as template to synthesize their
corresponding complementary strands
 Unwinding of dsDNA provides 2
ssDNA to be used as template
 There are 2 rules:
a)Rule of anti parallelism
b)Primer can grow only from 5’ to 3’
direction
 As DNAP can add nucleotides only
from 5’ to 3’ direction, synthesis in
one strand is continuous in the 5’ to 3’
direction towards the fork . This is
leading strand
 In the other strand, as the replication
fork opens, multiple sites of initiation
are exposed.
 The synthesis then proceeds in short
segments (okazaki fragments) in the 5’-3’
direction. This is lagging strand
Leading strand Lagging strand
Replicated strand of
DNA which grows
continuously
without any gap
Replicated strand of DNA
which is formed in short
segments (okazaki
fragments)
Its growth is
continuous
Its growth is
discontinuous
DNA ligase is not
required
DNA ligase is required for
joining okazaki fragments
Its template opens in
3’-5’ direction
Its template opens in 5’-3’
direction
Leading strand Lagging strand
The direction of growth of
leading strand is 5’-3’
The direction of growth of
lagging strand is 3’-5’ but in
okazaki fragment, it is 5’-3’
A single RNA primer is
required
Starting of each okazaki
fragment needs a new RNA
primer
Formation of leading
strand is quite rapid &
begins immediately at the
beginning of replication
Formation of lagging strand is
slower & begins a bit later
than that of leading strand
Steps
of
Replication
The process of DNA replication
comprises a set of carefully
orchestrated sequence of events to
duplicate the entire genetic content
of a cell.
Steps Prokaryotic Eukaryotic
Recognition of
ORI
dna-A protein unknown
Unwinding of
DNA double
helix
Helicase
(requires ATP)
Helicase
(requires ATP)
Stabilization
of unwound
template
strand
Single
stranded DNA
binding
protein (SSBP)
Single
stranded DNA
binding
protein (SSBP)
Synthesis of
RNA primer
Primase Primase
Steps Prokaryotic Eukaryotic
Synthesis of DNA:
Leading strand
Lagging strand
(okazaki
fragments)
DNAP III
DNAP III
DNAP-ε
DNAP-δ
Removal of RNA
primers & its
replacement with
DNA
DNAP I DNAP-β
Joining of okazaki
fragments
DNA Ligase
(requires
NAD)
DNA Ligase
(requires
ATP)
Steps Prokaryotic Eukaryotic
Solving of
topological
crisis
DNA
topoisomerase
DNA
topoisomerase
Synthesis of
telomeres
Not required Telomerase
All these steps are describedAll these steps are described
under three headingsunder three headings
Initiation:
 Identification of ORI
 Unwinding of a dsDNA to
provide a ssDNA template (role
of helicase)
 Formation of replication fork
 Synthesis of primer
Elongation:
 Attachment of primer with the
template (ssDNA)
 Synthesis of new / daughter DNA
complementary to template through
polymerization of dNTP by DNAP-δ
& DNAP-ε.
 Solving of topological crisis by
topoisomerase
 Excision of primer & its replacement
by DNAP-β
 Sealing of nicks & joining of okazaki
fragments by DNA ligase
Termination:
 Replication fork moves
bidirectionally from the ORI
until adjacent replication fork
fuse at opposite side when the
replication is completed
10/13/18Footer Text 59
Others:
a. Synthesis of new histones
b. Reconstitution of chromatin
structure with histones
SummarySummary
Importance
of
Replication
 It ensures the presence of complete
complement of DNA in each daughter
cell during cell division, so that
daughter cell DNA becomes identical
to that of parent cell
 It ensures duplication &
transmission of genetic information
from one generation to next
10/13/18Footer Text 63
64

More Related Content

What's hot

7 chromosomal aberrations
7 chromosomal aberrations7 chromosomal aberrations
7 chromosomal aberrations
mujahid hussain
 
Interference
InterferenceInterference
Interference
Meghna Thiruveedi
 
Presentation on Folded Fibre Model
Presentation on Folded Fibre ModelPresentation on Folded Fibre Model
Presentation on Folded Fibre Model
Dr. Kaushik Kumar Panigrahi
 
Numerical changes in chromosome
Numerical changes in chromosomeNumerical changes in chromosome
Numerical changes in chromosome
Jaleelkabdul Jaleel
 
Genetic Recombinition in Bacteria
Genetic Recombinition in BacteriaGenetic Recombinition in Bacteria
Genetic Recombinition in Bacteria
Asad Afridi
 
Gene regulation in prokaryotes
Gene regulation in prokaryotesGene regulation in prokaryotes
Gene regulation in prokaryotes
Jannat Iftikhar
 
Plant Tissue Culture - Organogenesis
Plant Tissue Culture - Organogenesis Plant Tissue Culture - Organogenesis
Plant Tissue Culture - Organogenesis
A Biodiction : A Unit of Dr. Divya Sharma
 
LINKAGE
LINKAGELINKAGE
Genetic recombination
Genetic recombinationGenetic recombination
Genetic recombination
AnuKiruthika
 
Gene isolation methods
Gene isolation methodsGene isolation methods
Gene isolation methods
Promila Sheoran
 
Types of mutation
Types of mutationTypes of mutation
Types of mutation
AnuKiruthika
 
Bacterial transformation
Bacterial transformationBacterial transformation
Bacterial transformation
ipezpagn91
 
Clonal Propagation: Introduction, Techniques, Factors, Applications and Disad...
Clonal Propagation: Introduction, Techniques, Factors, Applications and Disad...Clonal Propagation: Introduction, Techniques, Factors, Applications and Disad...
Clonal Propagation: Introduction, Techniques, Factors, Applications and Disad...
A Biodiction : A Unit of Dr. Divya Sharma
 
4. Gene interaction - Epistasis - Dominant & Recessive, Non-epistatsis
4. Gene interaction - Epistasis - Dominant & Recessive, Non-epistatsis4. Gene interaction - Epistasis - Dominant & Recessive, Non-epistatsis
4. Gene interaction - Epistasis - Dominant & Recessive, Non-epistatsis
Nethravathi Siri
 
Water potential and its components
Water potential and its componentsWater potential and its components
Water potential and its components
K040798s
 
Amensalism
Amensalism Amensalism
Amensalism
sandunikm
 
Maternal effects
Maternal effectsMaternal effects
Maternal effects
Vishakha Chodankar
 
factors affecting allele frequencies
factors affecting allele  frequenciesfactors affecting allele  frequencies
factors affecting allele frequencies
tammi-1990
 
Virus Transmission
Virus TransmissionVirus Transmission
Virus Transmission
Amna Jalil
 
Ecology lecture 1-2 (1-2-2023).pptx
Ecology lecture 1-2 (1-2-2023).pptxEcology lecture 1-2 (1-2-2023).pptx
Ecology lecture 1-2 (1-2-2023).pptx
Arbaz57
 

What's hot (20)

7 chromosomal aberrations
7 chromosomal aberrations7 chromosomal aberrations
7 chromosomal aberrations
 
Interference
InterferenceInterference
Interference
 
Presentation on Folded Fibre Model
Presentation on Folded Fibre ModelPresentation on Folded Fibre Model
Presentation on Folded Fibre Model
 
Numerical changes in chromosome
Numerical changes in chromosomeNumerical changes in chromosome
Numerical changes in chromosome
 
Genetic Recombinition in Bacteria
Genetic Recombinition in BacteriaGenetic Recombinition in Bacteria
Genetic Recombinition in Bacteria
 
Gene regulation in prokaryotes
Gene regulation in prokaryotesGene regulation in prokaryotes
Gene regulation in prokaryotes
 
Plant Tissue Culture - Organogenesis
Plant Tissue Culture - Organogenesis Plant Tissue Culture - Organogenesis
Plant Tissue Culture - Organogenesis
 
LINKAGE
LINKAGELINKAGE
LINKAGE
 
Genetic recombination
Genetic recombinationGenetic recombination
Genetic recombination
 
Gene isolation methods
Gene isolation methodsGene isolation methods
Gene isolation methods
 
Types of mutation
Types of mutationTypes of mutation
Types of mutation
 
Bacterial transformation
Bacterial transformationBacterial transformation
Bacterial transformation
 
Clonal Propagation: Introduction, Techniques, Factors, Applications and Disad...
Clonal Propagation: Introduction, Techniques, Factors, Applications and Disad...Clonal Propagation: Introduction, Techniques, Factors, Applications and Disad...
Clonal Propagation: Introduction, Techniques, Factors, Applications and Disad...
 
4. Gene interaction - Epistasis - Dominant & Recessive, Non-epistatsis
4. Gene interaction - Epistasis - Dominant & Recessive, Non-epistatsis4. Gene interaction - Epistasis - Dominant & Recessive, Non-epistatsis
4. Gene interaction - Epistasis - Dominant & Recessive, Non-epistatsis
 
Water potential and its components
Water potential and its componentsWater potential and its components
Water potential and its components
 
Amensalism
Amensalism Amensalism
Amensalism
 
Maternal effects
Maternal effectsMaternal effects
Maternal effects
 
factors affecting allele frequencies
factors affecting allele  frequenciesfactors affecting allele  frequencies
factors affecting allele frequencies
 
Virus Transmission
Virus TransmissionVirus Transmission
Virus Transmission
 
Ecology lecture 1-2 (1-2-2023).pptx
Ecology lecture 1-2 (1-2-2023).pptxEcology lecture 1-2 (1-2-2023).pptx
Ecology lecture 1-2 (1-2-2023).pptx
 

Similar to Replication (reviewed, 2018)

Replication
ReplicationReplication
Replication
enamifat
 
Replication
ReplicationReplication
Replication
enamifat
 
DNA Replication
DNA ReplicationDNA Replication
DNA Replication
Dr. A.D.Naveen Kumar
 
Replication of DNA
Replication of DNAReplication of DNA
Replication of DNA
Farhana Atia
 
dnareplication-151218084840 (1).pdf
dnareplication-151218084840 (1).pdfdnareplication-151218084840 (1).pdf
dnareplication-151218084840 (1).pdf
CYBEROCTAPAS
 
dna_replication.pptx
dna_replication.pptxdna_replication.pptx
dna_replication.pptx
GounderKirthika2
 
Dna replication b.pharm
Dna replication b.pharmDna replication b.pharm
Dna replication b.pharm
Kamlesh Yadav
 
Dna replication
Dna replicationDna replication
Dna replication
surendran aduthila
 
DNA Replication-2 in prokaryotes and eukaryotes.ppt
DNA Replication-2 in prokaryotes and eukaryotes.pptDNA Replication-2 in prokaryotes and eukaryotes.ppt
DNA Replication-2 in prokaryotes and eukaryotes.ppt
Sachin Teotia
 
DNA Replication
 DNA Replication DNA Replication
DNA Replication
Namrata Chhabra
 
Replication
ReplicationReplication
Replication
Dr.M.Prasad Naidu
 
Replication
ReplicationReplication
Replication
ammara12
 
DNA replication in prokaryotes
DNA replication in prokaryotes DNA replication in prokaryotes
DNA replication in prokaryotes
RanaMuhammadFurqan
 
Prof._Moushira_DNA replication.pdf
Prof._Moushira_DNA replication.pdfProf._Moushira_DNA replication.pdf
Prof._Moushira_DNA replication.pdf
SohailaGoda
 
DNA Replication in Prokaryotes and Eukaryotes .pptx
DNA Replication in Prokaryotes and Eukaryotes .pptxDNA Replication in Prokaryotes and Eukaryotes .pptx
DNA Replication in Prokaryotes and Eukaryotes .pptx
iftikharnarc1
 
Lecture 05.pdf
Lecture 05.pdfLecture 05.pdf
Lecture 05.pdf
TanvirFahim8
 
DNA Replication
DNA ReplicationDNA Replication
DNA Replication
Cyra Mae Soreda
 
Dna replication MBBS
Dna replication MBBSDna replication MBBS
Dna replication MBBS
Sohil Takodara
 
Dna replication lgis
Dna replication lgisDna replication lgis
Dna replication lgis
Zahid Azeem
 
DNA REPLICATION DAMAGE AND REPAIR
DNA REPLICATION DAMAGE AND REPAIRDNA REPLICATION DAMAGE AND REPAIR
DNA REPLICATION DAMAGE AND REPAIR
MSCW Mysore
 

Similar to Replication (reviewed, 2018) (20)

Replication
ReplicationReplication
Replication
 
Replication
ReplicationReplication
Replication
 
DNA Replication
DNA ReplicationDNA Replication
DNA Replication
 
Replication of DNA
Replication of DNAReplication of DNA
Replication of DNA
 
dnareplication-151218084840 (1).pdf
dnareplication-151218084840 (1).pdfdnareplication-151218084840 (1).pdf
dnareplication-151218084840 (1).pdf
 
dna_replication.pptx
dna_replication.pptxdna_replication.pptx
dna_replication.pptx
 
Dna replication b.pharm
Dna replication b.pharmDna replication b.pharm
Dna replication b.pharm
 
Dna replication
Dna replicationDna replication
Dna replication
 
DNA Replication-2 in prokaryotes and eukaryotes.ppt
DNA Replication-2 in prokaryotes and eukaryotes.pptDNA Replication-2 in prokaryotes and eukaryotes.ppt
DNA Replication-2 in prokaryotes and eukaryotes.ppt
 
DNA Replication
 DNA Replication DNA Replication
DNA Replication
 
Replication
ReplicationReplication
Replication
 
Replication
ReplicationReplication
Replication
 
DNA replication in prokaryotes
DNA replication in prokaryotes DNA replication in prokaryotes
DNA replication in prokaryotes
 
Prof._Moushira_DNA replication.pdf
Prof._Moushira_DNA replication.pdfProf._Moushira_DNA replication.pdf
Prof._Moushira_DNA replication.pdf
 
DNA Replication in Prokaryotes and Eukaryotes .pptx
DNA Replication in Prokaryotes and Eukaryotes .pptxDNA Replication in Prokaryotes and Eukaryotes .pptx
DNA Replication in Prokaryotes and Eukaryotes .pptx
 
Lecture 05.pdf
Lecture 05.pdfLecture 05.pdf
Lecture 05.pdf
 
DNA Replication
DNA ReplicationDNA Replication
DNA Replication
 
Dna replication MBBS
Dna replication MBBSDna replication MBBS
Dna replication MBBS
 
Dna replication lgis
Dna replication lgisDna replication lgis
Dna replication lgis
 
DNA REPLICATION DAMAGE AND REPAIR
DNA REPLICATION DAMAGE AND REPAIRDNA REPLICATION DAMAGE AND REPAIR
DNA REPLICATION DAMAGE AND REPAIR
 

More from enamifat

Thyroid Function test.pptx
Thyroid Function test.pptxThyroid Function test.pptx
Thyroid Function test.pptx
enamifat
 
Chemistry of protein, part 2 (Aug'21)
Chemistry of protein, part 2 (Aug'21)Chemistry of protein, part 2 (Aug'21)
Chemistry of protein, part 2 (Aug'21)
enamifat
 
Chemistry of protein, part 1 (Aug'21)
Chemistry of protein, part 1 (Aug'21)Chemistry of protein, part 1 (Aug'21)
Chemistry of protein, part 1 (Aug'21)
enamifat
 
Central Dogma, Gene, Genetic Code, Codon, Genome, Genotype, Phenotype , Trai...
Central Dogma, Gene,  Genetic Code, Codon, Genome, Genotype, Phenotype , Trai...Central Dogma, Gene,  Genetic Code, Codon, Genome, Genotype, Phenotype , Trai...
Central Dogma, Gene, Genetic Code, Codon, Genome, Genotype, Phenotype , Trai...
enamifat
 
Acid base balance (updated in 2020)
Acid base balance (updated in 2020)Acid base balance (updated in 2020)
Acid base balance (updated in 2020)
enamifat
 
Solution, crystalloids , colloids, isotope
Solution, crystalloids , colloids, isotope Solution, crystalloids , colloids, isotope
Solution, crystalloids , colloids, isotope
enamifat
 
Chemistry of lipid , september 2020
Chemistry of lipid , september 2020Chemistry of lipid , september 2020
Chemistry of lipid , september 2020
enamifat
 
Protein metabolism, july'20
Protein metabolism, july'20Protein metabolism, july'20
Protein metabolism, july'20
enamifat
 
Water soluble vitamins , june, 2020
Water soluble vitamins , june, 2020Water soluble vitamins , june, 2020
Water soluble vitamins , june, 2020
enamifat
 
Rna , ribosome and cell cycle, july 2020
Rna , ribosome and cell cycle, july 2020Rna , ribosome and cell cycle, july 2020
Rna , ribosome and cell cycle, july 2020
enamifat
 
Structure of dna, its organization & functions, july 2020
Structure of dna, its organization & functions, july 2020Structure of dna, its organization & functions, july 2020
Structure of dna, its organization & functions, july 2020
enamifat
 
Introduction to nucleic acid, chemistry of nucleotiides , july 2020
Introduction to nucleic acid, chemistry of nucleotiides , july 2020Introduction to nucleic acid, chemistry of nucleotiides , july 2020
Introduction to nucleic acid, chemistry of nucleotiides , july 2020
enamifat
 
Chemistry of enzyme
Chemistry of enzymeChemistry of enzyme
Chemistry of enzyme
enamifat
 
Chemistry of carbohydrates
Chemistry of carbohydratesChemistry of carbohydrates
Chemistry of carbohydrates
enamifat
 
Metabolism of protein
Metabolism of protein Metabolism of protein
Metabolism of protein
enamifat
 
Chemistry of protein
Chemistry of protein Chemistry of protein
Chemistry of protein
enamifat
 
Chemistry of digestion &; absorption
Chemistry of digestion &; absorption Chemistry of digestion &; absorption
Chemistry of digestion &; absorption
enamifat
 
Vitamins
Vitamins Vitamins
Vitamins
enamifat
 
Acid base balance, acid base disorder
Acid base balance, acid base disorderAcid base balance, acid base disorder
Acid base balance, acid base disorder
enamifat
 
Quality Assurance Program in Medical Education in Bangladesh, Part 1
Quality Assurance Program in Medical Education in Bangladesh, Part 1Quality Assurance Program in Medical Education in Bangladesh, Part 1
Quality Assurance Program in Medical Education in Bangladesh, Part 1
enamifat
 

More from enamifat (20)

Thyroid Function test.pptx
Thyroid Function test.pptxThyroid Function test.pptx
Thyroid Function test.pptx
 
Chemistry of protein, part 2 (Aug'21)
Chemistry of protein, part 2 (Aug'21)Chemistry of protein, part 2 (Aug'21)
Chemistry of protein, part 2 (Aug'21)
 
Chemistry of protein, part 1 (Aug'21)
Chemistry of protein, part 1 (Aug'21)Chemistry of protein, part 1 (Aug'21)
Chemistry of protein, part 1 (Aug'21)
 
Central Dogma, Gene, Genetic Code, Codon, Genome, Genotype, Phenotype , Trai...
Central Dogma, Gene,  Genetic Code, Codon, Genome, Genotype, Phenotype , Trai...Central Dogma, Gene,  Genetic Code, Codon, Genome, Genotype, Phenotype , Trai...
Central Dogma, Gene, Genetic Code, Codon, Genome, Genotype, Phenotype , Trai...
 
Acid base balance (updated in 2020)
Acid base balance (updated in 2020)Acid base balance (updated in 2020)
Acid base balance (updated in 2020)
 
Solution, crystalloids , colloids, isotope
Solution, crystalloids , colloids, isotope Solution, crystalloids , colloids, isotope
Solution, crystalloids , colloids, isotope
 
Chemistry of lipid , september 2020
Chemistry of lipid , september 2020Chemistry of lipid , september 2020
Chemistry of lipid , september 2020
 
Protein metabolism, july'20
Protein metabolism, july'20Protein metabolism, july'20
Protein metabolism, july'20
 
Water soluble vitamins , june, 2020
Water soluble vitamins , june, 2020Water soluble vitamins , june, 2020
Water soluble vitamins , june, 2020
 
Rna , ribosome and cell cycle, july 2020
Rna , ribosome and cell cycle, july 2020Rna , ribosome and cell cycle, july 2020
Rna , ribosome and cell cycle, july 2020
 
Structure of dna, its organization & functions, july 2020
Structure of dna, its organization & functions, july 2020Structure of dna, its organization & functions, july 2020
Structure of dna, its organization & functions, july 2020
 
Introduction to nucleic acid, chemistry of nucleotiides , july 2020
Introduction to nucleic acid, chemistry of nucleotiides , july 2020Introduction to nucleic acid, chemistry of nucleotiides , july 2020
Introduction to nucleic acid, chemistry of nucleotiides , july 2020
 
Chemistry of enzyme
Chemistry of enzymeChemistry of enzyme
Chemistry of enzyme
 
Chemistry of carbohydrates
Chemistry of carbohydratesChemistry of carbohydrates
Chemistry of carbohydrates
 
Metabolism of protein
Metabolism of protein Metabolism of protein
Metabolism of protein
 
Chemistry of protein
Chemistry of protein Chemistry of protein
Chemistry of protein
 
Chemistry of digestion &; absorption
Chemistry of digestion &; absorption Chemistry of digestion &; absorption
Chemistry of digestion &; absorption
 
Vitamins
Vitamins Vitamins
Vitamins
 
Acid base balance, acid base disorder
Acid base balance, acid base disorderAcid base balance, acid base disorder
Acid base balance, acid base disorder
 
Quality Assurance Program in Medical Education in Bangladesh, Part 1
Quality Assurance Program in Medical Education in Bangladesh, Part 1Quality Assurance Program in Medical Education in Bangladesh, Part 1
Quality Assurance Program in Medical Education in Bangladesh, Part 1
 

Recently uploaded

Thyroid Gland- Gross Anatomy by Dr. Rabia Inam Gandapore.pptx
Thyroid Gland- Gross Anatomy by Dr. Rabia Inam Gandapore.pptxThyroid Gland- Gross Anatomy by Dr. Rabia Inam Gandapore.pptx
Thyroid Gland- Gross Anatomy by Dr. Rabia Inam Gandapore.pptx
Dr. Rabia Inam Gandapore
 
Adhd Medication Shortage Uk - trinexpharmacy.com
Adhd Medication Shortage Uk - trinexpharmacy.comAdhd Medication Shortage Uk - trinexpharmacy.com
Adhd Medication Shortage Uk - trinexpharmacy.com
reignlana06
 
Histololgy of Female Reproductive System.pptx
Histololgy of Female Reproductive System.pptxHistololgy of Female Reproductive System.pptx
Histololgy of Female Reproductive System.pptx
AyeshaZaid1
 
Phone Us ❤8107221448❤ #ℂall #gIRLS In Dehradun By Dehradun @ℂall @Girls Hotel...
Phone Us ❤8107221448❤ #ℂall #gIRLS In Dehradun By Dehradun @ℂall @Girls Hotel...Phone Us ❤8107221448❤ #ℂall #gIRLS In Dehradun By Dehradun @ℂall @Girls Hotel...
Phone Us ❤8107221448❤ #ℂall #gIRLS In Dehradun By Dehradun @ℂall @Girls Hotel...
chandankumarsmartiso
 
Top-Vitamin-Supplement-Brands-in-India List
Top-Vitamin-Supplement-Brands-in-India ListTop-Vitamin-Supplement-Brands-in-India List
Top-Vitamin-Supplement-Brands-in-India List
SwisschemDerma
 
Integrating Ayurveda into Parkinson’s Management: A Holistic Approach
Integrating Ayurveda into Parkinson’s Management: A Holistic ApproachIntegrating Ayurveda into Parkinson’s Management: A Holistic Approach
Integrating Ayurveda into Parkinson’s Management: A Holistic Approach
Ayurveda ForAll
 
Dehradun #ℂall #gIRLS Oyo Hotel 8107221448 #ℂall #gIRL in Dehradun
Dehradun #ℂall #gIRLS Oyo Hotel 8107221448 #ℂall #gIRL in DehradunDehradun #ℂall #gIRLS Oyo Hotel 8107221448 #ℂall #gIRL in Dehradun
Dehradun #ℂall #gIRLS Oyo Hotel 8107221448 #ℂall #gIRL in Dehradun
chandankumarsmartiso
 
Tests for analysis of different pharmaceutical.pptx
Tests for analysis of different pharmaceutical.pptxTests for analysis of different pharmaceutical.pptx
Tests for analysis of different pharmaceutical.pptx
taiba qazi
 
A Classical Text Review on Basavarajeeyam
A Classical Text Review on BasavarajeeyamA Classical Text Review on Basavarajeeyam
A Classical Text Review on Basavarajeeyam
Dr. Jyothirmai Paindla
 
Best Ayurvedic medicine for Gas and Indigestion
Best Ayurvedic medicine for Gas and IndigestionBest Ayurvedic medicine for Gas and Indigestion
Best Ayurvedic medicine for Gas and Indigestion
Swastik Ayurveda
 
Does Over-Masturbation Contribute to Chronic Prostatitis.pptx
Does Over-Masturbation Contribute to Chronic Prostatitis.pptxDoes Over-Masturbation Contribute to Chronic Prostatitis.pptx
Does Over-Masturbation Contribute to Chronic Prostatitis.pptx
walterHu5
 
Cell Therapy Expansion and Challenges in Autoimmune Disease
Cell Therapy Expansion and Challenges in Autoimmune DiseaseCell Therapy Expansion and Challenges in Autoimmune Disease
Cell Therapy Expansion and Challenges in Autoimmune Disease
Health Advances
 
Muscles of Mastication by Dr. Rabia Inam Gandapore.pptx
Muscles of Mastication by Dr. Rabia Inam Gandapore.pptxMuscles of Mastication by Dr. Rabia Inam Gandapore.pptx
Muscles of Mastication by Dr. Rabia Inam Gandapore.pptx
Dr. Rabia Inam Gandapore
 
OCT Training Course for clinical practice Part 1
OCT Training Course for clinical practice Part 1OCT Training Course for clinical practice Part 1
OCT Training Course for clinical practice Part 1
KafrELShiekh University
 
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptx
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptx8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptx
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptx
Holistified Wellness
 
share - Lions, tigers, AI and health misinformation, oh my!.pptx
share - Lions, tigers, AI and health misinformation, oh my!.pptxshare - Lions, tigers, AI and health misinformation, oh my!.pptx
share - Lions, tigers, AI and health misinformation, oh my!.pptx
Tina Purnat
 
Journal Article Review on Rasamanikya
Journal Article Review on RasamanikyaJournal Article Review on Rasamanikya
Journal Article Review on Rasamanikya
Dr. Jyothirmai Paindla
 
Top Effective Soaps for Fungal Skin Infections in India
Top Effective Soaps for Fungal Skin Infections in IndiaTop Effective Soaps for Fungal Skin Infections in India
Top Effective Soaps for Fungal Skin Infections in India
SwisschemDerma
 
The Best Ayurvedic Antacid Tablets in India
The Best Ayurvedic Antacid Tablets in IndiaThe Best Ayurvedic Antacid Tablets in India
The Best Ayurvedic Antacid Tablets in India
Swastik Ayurveda
 
Ear and its clinical correlations By Dr. Rabia Inam Gandapore.pptx
Ear and its clinical correlations By Dr. Rabia Inam Gandapore.pptxEar and its clinical correlations By Dr. Rabia Inam Gandapore.pptx
Ear and its clinical correlations By Dr. Rabia Inam Gandapore.pptx
Dr. Rabia Inam Gandapore
 

Recently uploaded (20)

Thyroid Gland- Gross Anatomy by Dr. Rabia Inam Gandapore.pptx
Thyroid Gland- Gross Anatomy by Dr. Rabia Inam Gandapore.pptxThyroid Gland- Gross Anatomy by Dr. Rabia Inam Gandapore.pptx
Thyroid Gland- Gross Anatomy by Dr. Rabia Inam Gandapore.pptx
 
Adhd Medication Shortage Uk - trinexpharmacy.com
Adhd Medication Shortage Uk - trinexpharmacy.comAdhd Medication Shortage Uk - trinexpharmacy.com
Adhd Medication Shortage Uk - trinexpharmacy.com
 
Histololgy of Female Reproductive System.pptx
Histololgy of Female Reproductive System.pptxHistololgy of Female Reproductive System.pptx
Histololgy of Female Reproductive System.pptx
 
Phone Us ❤8107221448❤ #ℂall #gIRLS In Dehradun By Dehradun @ℂall @Girls Hotel...
Phone Us ❤8107221448❤ #ℂall #gIRLS In Dehradun By Dehradun @ℂall @Girls Hotel...Phone Us ❤8107221448❤ #ℂall #gIRLS In Dehradun By Dehradun @ℂall @Girls Hotel...
Phone Us ❤8107221448❤ #ℂall #gIRLS In Dehradun By Dehradun @ℂall @Girls Hotel...
 
Top-Vitamin-Supplement-Brands-in-India List
Top-Vitamin-Supplement-Brands-in-India ListTop-Vitamin-Supplement-Brands-in-India List
Top-Vitamin-Supplement-Brands-in-India List
 
Integrating Ayurveda into Parkinson’s Management: A Holistic Approach
Integrating Ayurveda into Parkinson’s Management: A Holistic ApproachIntegrating Ayurveda into Parkinson’s Management: A Holistic Approach
Integrating Ayurveda into Parkinson’s Management: A Holistic Approach
 
Dehradun #ℂall #gIRLS Oyo Hotel 8107221448 #ℂall #gIRL in Dehradun
Dehradun #ℂall #gIRLS Oyo Hotel 8107221448 #ℂall #gIRL in DehradunDehradun #ℂall #gIRLS Oyo Hotel 8107221448 #ℂall #gIRL in Dehradun
Dehradun #ℂall #gIRLS Oyo Hotel 8107221448 #ℂall #gIRL in Dehradun
 
Tests for analysis of different pharmaceutical.pptx
Tests for analysis of different pharmaceutical.pptxTests for analysis of different pharmaceutical.pptx
Tests for analysis of different pharmaceutical.pptx
 
A Classical Text Review on Basavarajeeyam
A Classical Text Review on BasavarajeeyamA Classical Text Review on Basavarajeeyam
A Classical Text Review on Basavarajeeyam
 
Best Ayurvedic medicine for Gas and Indigestion
Best Ayurvedic medicine for Gas and IndigestionBest Ayurvedic medicine for Gas and Indigestion
Best Ayurvedic medicine for Gas and Indigestion
 
Does Over-Masturbation Contribute to Chronic Prostatitis.pptx
Does Over-Masturbation Contribute to Chronic Prostatitis.pptxDoes Over-Masturbation Contribute to Chronic Prostatitis.pptx
Does Over-Masturbation Contribute to Chronic Prostatitis.pptx
 
Cell Therapy Expansion and Challenges in Autoimmune Disease
Cell Therapy Expansion and Challenges in Autoimmune DiseaseCell Therapy Expansion and Challenges in Autoimmune Disease
Cell Therapy Expansion and Challenges in Autoimmune Disease
 
Muscles of Mastication by Dr. Rabia Inam Gandapore.pptx
Muscles of Mastication by Dr. Rabia Inam Gandapore.pptxMuscles of Mastication by Dr. Rabia Inam Gandapore.pptx
Muscles of Mastication by Dr. Rabia Inam Gandapore.pptx
 
OCT Training Course for clinical practice Part 1
OCT Training Course for clinical practice Part 1OCT Training Course for clinical practice Part 1
OCT Training Course for clinical practice Part 1
 
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptx
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptx8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptx
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptx
 
share - Lions, tigers, AI and health misinformation, oh my!.pptx
share - Lions, tigers, AI and health misinformation, oh my!.pptxshare - Lions, tigers, AI and health misinformation, oh my!.pptx
share - Lions, tigers, AI and health misinformation, oh my!.pptx
 
Journal Article Review on Rasamanikya
Journal Article Review on RasamanikyaJournal Article Review on Rasamanikya
Journal Article Review on Rasamanikya
 
Top Effective Soaps for Fungal Skin Infections in India
Top Effective Soaps for Fungal Skin Infections in IndiaTop Effective Soaps for Fungal Skin Infections in India
Top Effective Soaps for Fungal Skin Infections in India
 
The Best Ayurvedic Antacid Tablets in India
The Best Ayurvedic Antacid Tablets in IndiaThe Best Ayurvedic Antacid Tablets in India
The Best Ayurvedic Antacid Tablets in India
 
Ear and its clinical correlations By Dr. Rabia Inam Gandapore.pptx
Ear and its clinical correlations By Dr. Rabia Inam Gandapore.pptxEar and its clinical correlations By Dr. Rabia Inam Gandapore.pptx
Ear and its clinical correlations By Dr. Rabia Inam Gandapore.pptx
 

Replication (reviewed, 2018)

  • 1. ReplicationReplication Dr Ifat Ara Begum Associate Professor Dept of Biochemistry Dhaka Medical College Dhaka 1
  • 2. Structure of DNAStructure of DNA 10/13/18Footer Text 2
  • 4. 10/13/18Footer Text 4 Chargaff's rule” A = T & C = G
  • 6. What is Replication?What is Replication? 6  Fundamental process by which cell copies its DNA to transfer the genetic information to daughter cells  DNA directed DNA synthesis  Base sequence of daughter DNA (newly synthesized DNA) is identical to the base sequence of parent DNA (template).  The major event in S-phase of cell cycle
  • 9. 9 Replication is the basis for the biological inheritance  Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease  Cell must replicate its DNA before division  Ultimately, exactly two identical semi- conserved chromosomes are produced
  • 10.
  • 14. Catalyzes joining of nucleotides to 3’- terminal of the growing chain (deoxynucleotides polymerization)
  • 15. Sealing the single strand nick & connecting okazaki fragments on lagging strand
  • 16. Relieves torsional strain resulting from helicase-induced unwinding
  • 17. Criteria / Features of ReplicationCriteria / Features of Replication 17  Semi conservative process: 50% of parental DNA is conserved in each of daughter DNA  Symmetric process: After unwinding of DS DNA, each of the 2 single stranded parental DNA serves as template for synthesis of new complementary daughter DNA  Copying of template always occurs from 3’ to 5’ direction & synthesis of new strand from 5’ to 3’ direction  Needs primer
  • 18. 18  Bidirectional process: From a specific ORI, replication proceeds in both direction  Process of high fidelity : As DNAP has proof reading property, replication is a process of high fidelity & there is no need of post replicational modification  Non selective process: The whole genome is copied  Semi discontinuous process: B/w two strands, one replicates continuously without interruption whereas the other one replicated discontinuously with interruption.
  • 19.
  • 20. Semi discontinuous DNA ReplicationSemi discontinuous DNA Replication
  • 21. Energy of replicationEnergy of replication 21  The nucleotides used for replication arrives as nucleoside tri phosphate i.e. the bases are with their own energy source for bonding
  • 23. 10/13/18Footer Text 23 1. DNA Polymerase
  • 24.
  • 25.
  • 26.
  • 27. TYPE FUNCTION DNAP-α  Initiation of DNA synthesis  Synthesis of primer DNAP-β  Excision of primer  DNA repair DNAP-γ Mitochondrial DNA replication with proof reading DNAP-δ Synthesis of lagging strand with proof reading DNAP-ε  Synthesis of leading strand with proof reading  DNA repair
  • 28. 10/13/18Footer Text 28 2. Origin Of Replication (ORI)
  • 29.
  • 30.
  • 31.
  • 32.
  • 34. 34 Functional unit of replication Replicated region of DNA centering a definite ORI Or Space between 2 adjacent origins Each replicon has origin, terminus and control elements of replication
  • 35. 10/13/18Footer Text 35 4. Replication bubble & Replication fork
  • 36. 36
  • 37.
  • 38.
  • 39. 10/13/18Footer Text 39 5. Topological crisis
  • 40. 40
  • 41. 41  Topological crisis is created when melting of DS DNA applies turning force creating positive super coiling forward to the unmelted DNA double helix.  It tends to cause cessation of further DNA separation due to torsional strain.  Topoisomerase relieves the torsional strain resulting from helicase-induced unwinding
  • 43.
  • 44. 10/13/18Footer Text 44 7. Leading strand & Lagging strand
  • 45. 45  In replication, both the strands of DNA acts as template to synthesize their corresponding complementary strands  Unwinding of dsDNA provides 2 ssDNA to be used as template  There are 2 rules: a)Rule of anti parallelism b)Primer can grow only from 5’ to 3’ direction
  • 46.  As DNAP can add nucleotides only from 5’ to 3’ direction, synthesis in one strand is continuous in the 5’ to 3’ direction towards the fork . This is leading strand
  • 47.  In the other strand, as the replication fork opens, multiple sites of initiation are exposed.  The synthesis then proceeds in short segments (okazaki fragments) in the 5’-3’ direction. This is lagging strand
  • 48. Leading strand Lagging strand Replicated strand of DNA which grows continuously without any gap Replicated strand of DNA which is formed in short segments (okazaki fragments) Its growth is continuous Its growth is discontinuous DNA ligase is not required DNA ligase is required for joining okazaki fragments Its template opens in 3’-5’ direction Its template opens in 5’-3’ direction
  • 49. Leading strand Lagging strand The direction of growth of leading strand is 5’-3’ The direction of growth of lagging strand is 3’-5’ but in okazaki fragment, it is 5’-3’ A single RNA primer is required Starting of each okazaki fragment needs a new RNA primer Formation of leading strand is quite rapid & begins immediately at the beginning of replication Formation of lagging strand is slower & begins a bit later than that of leading strand
  • 51. The process of DNA replication comprises a set of carefully orchestrated sequence of events to duplicate the entire genetic content of a cell.
  • 52. Steps Prokaryotic Eukaryotic Recognition of ORI dna-A protein unknown Unwinding of DNA double helix Helicase (requires ATP) Helicase (requires ATP) Stabilization of unwound template strand Single stranded DNA binding protein (SSBP) Single stranded DNA binding protein (SSBP) Synthesis of RNA primer Primase Primase
  • 53. Steps Prokaryotic Eukaryotic Synthesis of DNA: Leading strand Lagging strand (okazaki fragments) DNAP III DNAP III DNAP-ε DNAP-δ Removal of RNA primers & its replacement with DNA DNAP I DNAP-β Joining of okazaki fragments DNA Ligase (requires NAD) DNA Ligase (requires ATP)
  • 54. Steps Prokaryotic Eukaryotic Solving of topological crisis DNA topoisomerase DNA topoisomerase Synthesis of telomeres Not required Telomerase
  • 55. All these steps are describedAll these steps are described under three headingsunder three headings
  • 56. Initiation:  Identification of ORI  Unwinding of a dsDNA to provide a ssDNA template (role of helicase)  Formation of replication fork  Synthesis of primer
  • 57. Elongation:  Attachment of primer with the template (ssDNA)  Synthesis of new / daughter DNA complementary to template through polymerization of dNTP by DNAP-δ & DNAP-ε.  Solving of topological crisis by topoisomerase  Excision of primer & its replacement by DNAP-β  Sealing of nicks & joining of okazaki fragments by DNA ligase
  • 58. Termination:  Replication fork moves bidirectionally from the ORI until adjacent replication fork fuse at opposite side when the replication is completed
  • 60. Others: a. Synthesis of new histones b. Reconstitution of chromatin structure with histones
  • 63.  It ensures the presence of complete complement of DNA in each daughter cell during cell division, so that daughter cell DNA becomes identical to that of parent cell  It ensures duplication & transmission of genetic information from one generation to next 10/13/18Footer Text 63
  • 64. 64