What is the function of helicase in dna replication? what is the function of helicase in dna replication? it checks for errors in the newly synthesized dna strand. it relieves strain from twisting of the double helix as it is unwound. it adds nucleotides to the new strand in the 5' to 3' direction. it untwists the double helix and separates the two dna strands. it joins together okazaki fragments?