When replication starts, an origin of replication forms, consisting of two moving in opposite directions. dna double helix is separated into single strands by the enzyme . newly-exposed, unreplicated dna is protected by . short segments of rna are synthesized, called . the enzyme that synthesizes the short segments of rna is called a . the short rna segments provide a free for replication. new dna is synthesized in the direction. the enzyme that removes tightened coils ahead of the replication fork is . the enzyme that catalyzes new dna synthesis is . dna synthesis occurs continuously on the . dna synthesis occurs in small sections on the . fragments of discontinuous dna synthesis are called . gaps in the sugar-phosphate backbone of dna are closed by .