Final answer:
The primary enzyme for DNA strand elongation during eukaryotic replication is DNA polymerase delta (pol δ), which takes over after DNA polymerase alpha (pol α) initiates replication.
Step-by-step explanation:
The primary DNA synthesizing enzyme during replication in eukaryotes is DNA polymerase delta (pol δ).
Eukaryotic cells utilize multiple DNA polymerases during the replication process. DNA polymerase alpha (pol α) initiates replication by synthesizing a short RNA primer with a limited number of DNA nucleotides attached. Afterward, DNA polymerase delta (pol δ) takes over the majority of DNA strand elongation, and it works closely with a protein known as PCNA, the proliferating cell nuclear antigen. Additionally, DNA polymerase epsilon (pol ε) is similar in structure and function to DNA polymerase delta, although pol ε predominantly synthesizes the leading strand, while pol δ focuses on the lagging strand synthesis. The intricacy of the eukaryotic system extends to a process using over a dozen polymerases, contrasting with prokaryotes, which primarily use DNA polymerase III for DNA strand elongation.