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#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.