Final answer:
DNA replication occurs in the 5' to 3' direction, with the leading strand synthesized continuously and the lagging strand in Okazaki fragments. DNA polymerase adds nucleotides only to the 3' end, creating a new strand from 5' to 3'. Okazaki fragments are joined by DNA ligase to form a continuous lagging strand.
Step-by-step explanation:
DNA replication proceeds in the 5' to 3' direction. This means that the DNA polymerase enzyme can add nucleotides only to the 3' end of the newly forming strand, building the strand in a 5' to 3' direction. The replication process is semiconservative and occurs simultaneously on two strands, namely the leading strand and the lagging strand.
The leading strand is synthesized continuously towards the replication fork, as it is complementary to the parental 3' to 5' DNA template strand, allowing the DNA polymerase to add nucleotides in one uninterrupted action. In contrast, the lagging strand, which is complementary to the 5' to 3' parental DNA template, is synthesized discontinuously. It is made in short segments called Okazaki fragments, which are later joined together by the enzyme DNA ligase to form a continuous strand. These fragments allow replication to proceed in the overall 5' to 3' direction, even though each individual segment grows in the 3' to 5' direction before being stitched together.
This replication process is essential for cell division and the maintenance of the genetic information from one generation to the next. The linkage of nucleotides in the DNA molecule is through a phosphodiester linkage, which is a strong covalent bond that ensures the integrity of the DNA molecule.