2. INTRODUCTON:-
1.A DNA polymerase is an enzyme that catalyzes the
polymerization of deoxyribonucleotides into a DNA strand
3. These enzyme are essential for DNA replication
2. Efficient machinery is required to maintain the genetic
information.
4. Eukaryotes have five DNA polymerases (pol): alpha,
beta, gamma, delta, and epsilon (α, β, γ, δ, and ε)which
are the key enzymes required to maintain the integrity of
the genome.
5. DNA polymerases can be further subdivided into seven
different families: A, B, C, D, X, Y, and RT.
3.
4.
5. PROPERTIES
1. DNA polymerase works at very high pace .it adds 2000 neucleotide
bases per sec in prokaryotes and 1000 bases per sec in eukaryotes.
3. It always needs a primer sequence of 20 neuleotide bases for
initiation of replication
4. It is not able to initiate the replication process. It can only elongates
the primer by adding neucleotide bases.
5. DNA polymerase always moves in 5’-3’ direction .
6. STRUCTURE
1.DNA polymerase is
akin to human hand
2.Having Fingers
Thumb Palm
Thriodoxin domin
Exonuclesase domin
3.DNA polymerase is
a dimer
7. FUNCTION
DNA REPLICATION
Once primase has created the RNA
primer DNA Pol alpha elongates that primer with DNA
neucleotides after around 20 nucleotides elongation
is taken over by Pol eta at leadind strand and by Pol
delta on lagging strand.
DNA PROOFREADING
DNA REPAIR
Any damage or change occurred in DNA is
recovered by DNA polymerase .it will add correct bases in
damaged part and borken bonds are again formed. in this
way structure of DNA is recovered again.
8.
9. IMPORTANCE
Having its role in DNA replication DNA polymerase
holds great importance for existance of life.
in Cell divison it confirms the exact
copy of genome.
Due to its proof reading ability it eliminat many kind
of mutations including point mutation caused by
wrong insertion of any one base .or the mutations
caused by deletion, addition, translocation and
inversion .
