Which pattern characterizes the lagging strand?

Which pattern characterizes the lagging strand?

• A. Continuous synthesis
• B. No synthesis
• C. Discontinuous synthesis
• D. Random synthesis

Answer: (C)

Discontinuous synthesis on the lagging strand happens because DNA polymerase can only add nucleotides in the 5' to 3' direction and the strands run antiparallel. The lagging strand’s template looks 5' to 3' toward the fork, so the polymerase can’t make a long continuous copy in that direction. Instead, primers are laid near the fork and short segments are synthesized away from the fork in the 5' to 3' direction. These short pieces, called Okazaki fragments, are later stitched together by ligase to form a complete lagging strand. This pattern—short, separate fragments rather than a single continuous strand—is what characterizes the lagging strand. Continuous synthesis would describe the leading strand, no synthesis would stop replication, and random synthesis doesn’t reflect the controlled, directional nature of DNA polymerase activity.

Discontinuous synthesis on the lagging strand happens because DNA polymerase can only add nucleotides in the 5' to 3' direction and the strands run antiparallel. The lagging strand’s template looks 5' to 3' toward the fork, so the polymerase can’t make a long continuous copy in that direction. Instead, primers are laid near the fork and short segments are synthesized away from the fork in the 5' to 3' direction. These short pieces, called Okazaki fragments, are later stitched together by ligase to form a complete lagging strand. This pattern—short, separate fragments rather than a single continuous strand—is what characterizes the lagging strand. Continuous synthesis would describe the leading strand, no synthesis would stop replication, and random synthesis doesn’t reflect the controlled, directional nature of DNA polymerase activity.