Final answer:
The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is synthesized in short fragments called Okazaki fragments in the opposite direction. The replisome treats the leading and lagging strands differently, with continuous synthesis on the leading strand and the need for RNA primers and fragment synthesis on the lagging strand.
Step-by-step explanation:
The leading strand and lagging strand are involved in DNA replication to ensure the accurate and efficient synthesis of new DNA strands. The leading strand is synthesized continuously in the 5' to 3' direction as the replication fork moves, while the lagging strand is synthesized in short fragments called Okazaki fragments in the opposite direction. This is because DNA polymerase can only add nucleotides to the free 3' end of the chain, limiting continuous synthesis on both strands.
The leading strand is treated differently by the replisome as it can be extended from a single primer, while the lagging strand requires a new primer for each Okazaki fragment. The lagging strand is synthesized by a complex of proteins called the replisome, which includes the enzyme primase that synthesizes RNA primers for each fragment. DNA polymerase then adds deoxyribonucleotides to the 3' end of each RNA primer, and the fragments are eventually joined together by DNA ligase.