(i) In long DNA molecules, since the two strands of DNA cannot be separated in its entire length, the replication occur within a small opening to the DNA helix, referred to as a replication fork.
(ii) The DNA-dependent DNA polymerases catalyse polymerization of the nucleotides only in 5' ---> 3' direction.
Consequently, on one of the template strands (with 3' --> 5' polarity) the synthesis of DNA is continuous, . while on the other template strand (with polarity 5' ---> 3'), the synthesis of DNA is discontinuous, i.e., short stretches of DNA are synthesized.
(iii) The discontinuously synthesized strands are later joined together by the enzyme DNA ligase.
