ORC is an initiation complex whose binding identifies an origin of replication.

TLS Online TPP Program

#Id: 6032

#Unit 3. Fundamental Processes

Synthesis of an Okazaki fragment displaces the RNA primer of the preceding fragment in the form of a “flap.”

the base of the flap is cleaved by the enzyme FEN1 (f lap endonuclease 1).  In this reaction, FEN1 functions as an endonuclease, but it also has a 5’–3’; exonuclease activity. In DNA repair reactions, FEN1 may cleave next to a displaced nucleotide and then use its exonuclease activity to remove adjacent material.

TLS Online TPP Program

#Id: 6033

#Unit 3. Fundamental Processes

Failure to remove a flap rapidly can have important consequences in regions of repeated sequences such as deletion and duplication

TLS Online TPP Program

#Id: 6034

#Unit 3. Fundamental Processes

Direct repeats can be displaced and misaligned with the template; palindromic sequences can form hairpins. These structures may change the number of repeats. The general importance of FEN1 is that it prevents flaps of DNA from generating structures that may cause deletions or duplications in the genome.

TLS Online TPP Program

#Id: 6035

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 6097

#Unit 3. Fundamental Processes

The shifts of hydrogen atoms between the number 3 and number 4 positions of the pyrimidines and between the number 1 and number 6 positions of the purines change their base-pairing potential due to Tautomeris

TLS Online TPP Program

#Id: 6098

#Unit 3. Fundamental Processes

Tautomerism is most common spontaneous form of mutagenic event which causes transition during replication