How is the lagging strand synthesized during DNA replication?

The lagging strand is synthesized discontinuously as short segments called Okazaki fragments. This occurs because DNA polymerase can only synthesize DNA in the 5' to 3' direction. During DNA replication, the two strands unwind and separate. While one strand, known as the leading strand, can be synthesized continuously in the same direction as the replication fork is opening, the lagging strand must be synthesized in the opposite direction.

As the replication fork opens, short stretches of the lagging strand are synthesized as Okazaki fragments, which are later connected by the enzyme DNA ligase. This process is necessary because the DNA polymerase must periodically return to the replication fork to continue synthesizing new fragments, making the overall synthesis of the lagging strand a stepwise process.

The other choices do not accurately describe how the lagging strand is formed. Continuous synthesis or circular synthesis does not reflect the nature of lagging strand synthesis, and while RNA nucleotides play a role in the initiation of replication, they are not the building blocks of the lagging strand's DNA. Thus, the correct understanding of the lagging strand's synthesis as occurring in fragments is crucial in grasping the overall mechanism of DNA replication.