Master the 2026 DNA Replication Challenge – Unlock the Secrets of DNA Storage!

The question tests how DNA is copied in replication. DNA polymerase only adds nucleotides in the 5′ to 3′ direction, so the strand running 3′ to 5′ toward the fork can be copied continuously as the fork opens—that’s the leading strand. The other parental strand runs 5′ to 3′ toward the fork, so synthesis must proceed away from the fork in short segments (Okazaki fragments) that are later stitched together; this is the lagging strand, synthesized discontinuously. The terms “template strand” and “coding strand” relate to transcription terminology and aren’t describing the replication-as-synthesis pattern here. So the strand synthesized discontinuously is the lagging strand.