what is the basis for the difference in how the leading and lagging strands of dna molecules are synthesized? responses the origins of replication occur only at the 5' end the origins of replication occur only at the 5' end helicases and topoisomerase work at the 5' end helicases and topoisomerase work at the 5' end dna polymerase can join new nucleotides only to the 3' end of a strand dna polymerase can join new nucleotides only to the 3' end of a strand ligase only works in the 3' to 5' direction
