During replication we can find it out that in one strand the synthesis would be complete and in the other strand the synthesis of deoxyribonucleic acid (DNA) would be discontinuous. We should keep in mind that DNA polymerase enzyme cannot by itself initiate a replication process; it needs hydroxyl group at the 3? end of the DNA growing chain.
Since in a DNA strand both the DNA molecules are found complementary to each other with one strand running in the 3?-5? direction, and the other strand running from the 5?-3? direction. Continuous synthesis would be present in the strand that runs from the 5?-3? direction, where the DNA would be growing in the 3?-5? direction. The DNA polymerase enzyme adds nucleotides to the 3? end of the DNA containing the hydroxyl group. In the other strand that runs from 3?-5? direction, the synthesis would happen in the same direction, but against the movement of the replication fork created by the helicase enzyme.
In the replication fork, in a lagging strand every time the fork travels forward the movement of DNA polymerase would be restricted till the end of the fork. New primers would be added at the region, where the replication fork moves forward. This would be used by the DNA polymerase elongating length of the DNA through the nucleotides till the end of the replication fork until it moves further.
Hence, when the replication fork moves further, the primer would be removed and this gap would be left as such. Such gaps formed would keep the two newly formed segments apart. These small segments are termed Okazaki fragments. This is the reason why in the lagging strand there are discontinuous strands as opposed to the other end containing continuous strand.