Final answer:
DNA polymerization always occurs in the 5' to 3' direction for both the leading and lagging strands during DNA replication due to the action of DNA polymerase enzymes which can only add nucleotides to the 3' end of a growing DNA strand. The leading strand is synthesized continuously while the lagging strand is synthesized in Okazaki fragments, which are later joined together.
Step-by-step explanation:
DNA polymerization is a crucial aspect of DNA replication which involves the addition of nucleotides to a growing DNA strand. DNA polymerase enzymes catalyze this process, and they require a template strand on which to build the new strand. DNA polymerases are only able to add nucleotides to the free 3' end of the chain, which dictates that DNA polymerization occurs in the 5' to 3' direction. This is true for both prokaryotic and eukaryotic organisms, regardless of whether the strand being synthesized is the leading or lagging strand.
The leading strand is synthesized continuously in the direction of the replication fork, which means it is being elongated as the replication machinery moves forward. On the other hand, the lagging strand is synthesized in small, discontinuous segments known as Okazaki fragments because DNA polymerase must work in the opposite direction of the replication fork's movement for this strand. Each fragment begins with a short RNA primer, which is later replaced by DNA, and the fragments are eventually joined together by the enzyme DNA ligase.
Therefore, the correct answer is that DNA polymerization is always 5' to 3', regardless of whether it's occurring on the leading or lagging strand or in prokaryotic or eukaryotic cells.