Which strand is synthesized continuously during DNA replication?

Which strand is synthesized continuously during DNA replication?

• A. Leading strand
• B. Lagging strand
• C. Okazaki fragments
• D. DNA ligase

Answer: (A)

DNA synthesis proceeds in the 5' to 3' direction, so the strand whose template runs 3' to 5' toward the replication fork can be built in one smooth, continuous run as the fork opens. This continuous synthesis toward the fork is the leading strand, formed in a single, unbroken chain as the replication machinery advances. The opposite template runs 5' to 3' toward the fork, which forces synthesis to occur in short segments away from the fork. These short pieces are later stitched together by DNA ligase to make a continuous strand. Those fragments are known as Okazaki fragments, and they characterize the lagging strand. Thus, the strand that is synthesized continuously during DNA replication is the leading strand.

DNA synthesis proceeds in the 5' to 3' direction, so the strand whose template runs 3' to 5' toward the replication fork can be built in one smooth, continuous run as the fork opens. This continuous synthesis toward the fork is the leading strand, formed in a single, unbroken chain as the replication machinery advances.

The opposite template runs 5' to 3' toward the fork, which forces synthesis to occur in short segments away from the fork. These short pieces are later stitched together by DNA ligase to make a continuous strand. Those fragments are known as Okazaki fragments, and they characterize the lagging strand.

Thus, the strand that is synthesized continuously during DNA replication is the leading strand.