Question

As the two parental (template) DNA strands separate at a replication fork, each of the strands is separately copied by a DNA polymerase III (orange), producing two new daughter strands (light blue), each complementary to its respective parental strand. Because the two parental strands are antiparallel, the two new strands (the leading and lagging strands) cannot be synthesized in the same way.

Answer 1

It is true that because of the antiparallel direction the two new strands which are called leading and lagging strands are not synthesized in the same way.

The leading strand is synthesized in the direction of replication fork so it is synthesized continuously in 5' to 3' direction. As it is synthesized continuously only one primer is required for the formation of the leading strand.

The lagging strand is synthesized in the opposite direction of replication fork therefore it is synthesized in a discontinuous manner. So many primers are required for making lagging strand and the segment of DNA formed in the lagging strand are called Okazaki fragments.

These fragments are sealed by the action of the ligase enzyme. Lagging strand is also synthesized in 5' to 3' direction.