Final answer:
In DNA replication, only one primer is required for the leading strand, while multiple primers are necessary for the lagging strand to initiate the synthesis of Okazaki fragments. The RNA primers are replaced with DNA, and DNA ligase seals the gaps between fragments.
Step-by-step explanation:
During DNA replication, primers are short sequences of nucleotides that provide a starting point for DNA synthesis. On the leading strand, only one primer is needed, as DNA polymerase can continue adding nucleotides in a continuous manner. However, on the lagging strand, multiple primers are required, as replication occurs in short segments known as Okazaki fragments. Each fragment necessitates a new primer for DNA polymerase to extend the strand. The primers utilized are typically RNA strands, which are later removed and replaced with DNA by the enzyme DNA Pol I. Subsequently, the enzyme DNA ligase seals the gaps between the newly replaced DNA and the existing DNA.