molecular biology study , and learn how DNA get duplicate to transfer her material to new one {offspring} msc-2nd sem concept, BSc syllabus included , life science, biotechnology, zoology, 12th NEET important

1. Eukaryotes
Presented by –
Dharti B. Bandarwar
M.Sc. Sem-II [ZOOLOGY]
Guided by:- Dr. Swati Koushik
IOS Nagpur
Dt. 18-04-22

2. Synapsis…
Introduction
History
Types of replication
 Requirements
Replication Mechanism
Prokaryotic & eukaryotic
Conclusion
Reference

3. Introduction…
facts..
• Define:- Mechanism by which makes a copy of itself.
DNA DNA
• DNA has to be copied before a cell divides.
• occurs during s-phase (synthesis phase) of cell division.
• New cell will need identical DNA strands.
• Produce exact copies of parent DNA.
Double strand DNA Dissolution of hydrogen
bonds
Single strand DNA
Complementary
DNA

4. History…
• Watson and Crick proposed the outline model of
DNA replication. (1953)
• 1955 Arthur kornberg work with E.coli
Discovered the mechanism of DNA synthesis
• Replication of DNA confirmed by Matthew
Meselson and Stahl. (1957)
Watson and crick
on field work
Matthew and
Stahl [1959]

5. Types of Replication
properties:-
1. DNA
2. On the basis of complementary chain arrangement with
parent (template)DNA
Replication
DNA DNA{Replication}
Autocatalytic
DNA RNA {Replication}
Heterocatalytic
CONSERVATIVE
SEMI-
CONSERVATIVE
DISPERSIVE

6. Replication type
continue:-
Evidence of semiconservative
replication.
The experiment carried out by
Meselson and Stahl involved growing
of E.coli in a medium containing
NH4CL.
Cell were then transferred to normal
medium & sample taken after 20 &40
min.

7. Requirements…
Enzymes & proteins
• DNN Template, origin, dNTps, Mg2+
• DNA helicase- separates the two strand of DNA.
• DNA polymerase- catalyzing the addition substrates to DNA.
also perform proof reading and error. [pro-3, Eu-6]
• DNA clamp- protein which prevents elongating DNA polymerases from dissociating from
the DNA parent strand.
• Single strand DNA-binding protein- prevents double helix reannealing after unwinding.
• Topoisomerase- relax the DNA from its super coil nature.
• DNA ligase- Re-anneals the semiconservative strands and joins Okazaki fragments of the
lagging strand.
• DNA gyrase- relieves strain of unwinding by DNA helicase.
• Primase- provides starting point of RNA(or DNA) for DNA polymerase.
• Telomerase- lengthens telomeric DNA.

8. Replication mechanism
Eukaryotic cell
• Step 1 :- Activation of all the nucleotides [dNTPs]
• Step 2 :- origin of replication
• With respect cell
• Step3 :- NICK/CUT/Incision in DNA [Endonuclease]
• Step 4:- unwinding/unzipping of DNA [DNA helicase/rep protein]
A T G C
• Step5:- use of SSBP [single stranded binding protein]
Prokaryote - small DNA [one origin]
Eukaryote - large DNA [many origin]
Less energy More energy
Three major process.
1. Initiation
2. Elongation
3. termination

9. Mechanism continue….
• Step 6:- release of tension due to unwinding of DNA.[ topo isomerase (DNA
gyrase)]
• Step7:- Formation of RNA primer [DNA Primase]
• Step8 :- synthesis of new DNA strand [DNA polymerase]

10. Differences…
Prokaryotic replication
1. Occurs- cytoplasm
2. Rolling circle model
3. Only one replicon
4. Begins at single point
5. One replication eye
6. Fork is ɵ-(theta)
7. RNA primer 50 nucleotide
8. Okazaki fragment 1000 to 2000 nucleotide
9. Polymerization-polymerase III
10. Speed – heigh
11. Taken 40 min.
12. 1500 nucleotide/sec
Eukaryotic replication
1. Occurs- nucleus
2. linear
3. Many replicon
4. many, thousands of point
5. Many replication eye
6. Fork is Y-shaped
7. RNA primer 9 nucleotide
8. Okazaki fragment is 100 to 200 nucleotide
9. Polymerization- polymerase delta
10. speed-low
11. Takes 8 hrs.
12. 10to100/sec

11. Conclusion…
• The discoveries of DNA function aid us in
understanding how cellular process takes
• It is an essential function of material. DNA is
significant in the production of cells through
the mechanism of mitosis and meiosis.
• And also provide us with many tools to exploit
in the laboratory.

12. Reference…
• Life science vol-2- Pathfinder publication
• The cell biology – Saras publication
• https://youtu.be/ihjykvQGJps