What are the three steps of excision repair?

The basic mechanism of excision repair involves: (1) damage recognition; (2) subunit assembly; (3) dual incisions that result in excision of the damage-containing oligomer; (4) resynthesis to fill in the gap; and (5) ligation to regenerate an intact molecule.

What are the two types of excision repair?

Three different types of excision repair have been characterized: nucleotide excision repair, base excision repair, and mismatch repair.

How does excision repair work?

Excision repair involves removal of a damaged nucleotide by dual incisions bracketing the lesion; this is accomplished by a multisubunit enzyme referred to as the excision nuclease or excinuclease.

Can excision repair cause mutations?

If the improper uracils or thymines in these base pairs are not removed before DNA replication, they will cause transition mutations.

In what situation would excision repair be needed?

Nucleotide Excision Repair of DNA Damage NER is predominantly invoked in response to genomic damage caused by UV exposure and is also a substantially more complex process that includes at least 30 different proteins.

What causes base excision repair?

base excision repair, pathway by which cells repair damaged DNA during DNA replication. Base excision repair helps ensure that mutations are not incorporated into DNA as it is copied.

What is excision repair of DNA?

In nucleotide excision repair DNA damage is removed through incision of the damaged strand on both sides of the lesion, followed by repair synthesis, which fills the gap using the intact strand as a template, and finally ligation.

How SOS repair mechanism is different from other repair system?

The SOS system has enhanced DNA-repair capacity, including excision and post-replication repair, enhanced mutagenesis, prophage induction. The system can also inhibit cell division and cell respiration. The SOS response has been proposed as a model for bacterial evolution of certain types of antibiotic resistance.

What is the most damaging mutation?

Insertion or deletion, which leads to frameshift mutation is more damaging. It causes changes in the subsequent amino acid sequences in a polypeptide chain. Point mutation only alters one amino acid, whereas frameshift mutation alters the whole sequence of amino acids following the mutation.