DNA repair mechanism and their types

1. TOPIC-DNA REPAIR MECHANISM
AND THEIR TYPES

2. WHY DNA NEEDS TO BE REPAIRED ?
� Rna and proteins can be replaced by the information encoded in the
DNA molecule, but DNA itself cant’be replaced by a new DNA when
gets damaged.
� Unrepaired DNA leads to cancer production.
� Thus ,needs repair.
� MUTATION:A permanent change n the nucleotide bae of the DNA is
called ‘mutation’.
� Conequences of unrepaired DNA
� xer oderma pigmentation.

3. DNA REPAIR
� DNA repair is a collection of processes by which a cell
identifies and corrects damage to the DNA molecules that encode is
genome.There are several types to repair mechanism according to the types
of DNA damage

4. � 1.Base repair:1. Excision, 2.Re synthesis, 3.Ligation

5. � 3.Nucleotide excision repair(Methyl –directed mismatch
repair)
� Identification of mismatch stand
� repair of damaged DNA
� 4.Mismatch repair.

6. � Repair of double stranded break
� 1.Non-homologous end –joining repair.
� 2.Homologous recombination repair.