DNA Replication Practice Worksheet illustrating the S phase process with a replication fork, leading and lagging strands, Okazaki fragments, DNA polymerase, and strand polarity.

- Label the 5' and 3' ends on all four strands of DNA (the two original template strands and the two new daughter strands). The 5' end is at the top of each strand, and the 3' end is at the bottom.
- Identify the replication fork as the Y-shaped region where the double helix is unwound.
- On the left side of the fork, the top strand (template) runs 3' to 5' toward the fork; the new strand synthesized here is the leading strand, built continuously in the 5' to 3' direction away from the fork. Label this strand "leading strand".
- On the right side of the fork, the top strand (template) runs 5' to 3' toward the fork; the new strand synthesized here is the lagging strand, built discontinuously in short segments (Okazaki fragments) in the 5' to 3' direction away from the fork. Label this strand "lagging strand".
- Label the short, newly synthesized DNA segments on the lagging strand as "Okazaki fragments".
- Label the purple enzyme complexes synthesizing the new DNA strands as "DNA polymerase". There are three shown: one on the leading strand and two on the lagging strand (one for each Okazaki fragment being extended).