DNA Repair Mechanism And Their Types

1. z
DNA Repair Mechanism
And Their Types

2. z
DNA Repair :-
 The process of
immediately
correction of
temporary
damaged DNA is
known as DNA
repair.

3. z
Why DNA needs to be repaired ?
 RNA and proteins can be replaced by the information encoded in
the DNA molecule, but DNA itself can’t be replaced by a new
DNA when gets damaged.
 Unrepaired DNA leads to cancer production.
 Thus, needs repair.

4. z
DNA repair mechanism :-
1. Direct reversal :-
Some DNA damaging chemical
reactions can be directly “undone”
by enzymes in the cell.
a) Photoreactivation
b) Removal of methyl groups

5. z
2. Excision repair :-
Damage to one or a few bases of DNA is often fixed by removal
(excision) and replacement of the damaged region.
a) Base excision repair
b) Nucleotide excision repair

6. z
3. Mismatch repair :-
DNA mismatch repair
(MMR) is a system for
recognizing and repairing
erroneous insertion,
deletion, and mis-
incorporation of bases that
can arise during DNA
replication and
recombination, as well as
repairing some forms of
DNA damage.

7. z
4. Double-stranded break repair :-
Double-stranded breaks are
dangerous because large
segments of chromosomes, and
the hundreds of genes they
contain, may be lost if the
break is not repaired easily.
a) Non-homologous end
joining
b) Homologous recombination
pathways

8. z
THANK YOU