Question

Which one of the following factors significantly contributes to the ability of eukaryotic cells to complete DNA replication during the short window of time offered by S phase? Which one of the following factors significantly contributes to the ability of eukaryotic cells to complete DNA replication during the short window of time offered by S phase?

A. Eukaryotic DNA polymerases have dramatically increased processivity compared to DNA polymerases in organisms with smaller genomes.
B. Multiple origins of replication are activated per chromosome.
C. Origins of replication can initiate again after they have been replicated and before mitosis.
D. The next round of replication begins before the cell exits S phase.

Answer 1

B. Multiple origins of replication are activated per chromosome.

Step-by-step explanation:

DNA replication runs in 2 directions (bidirectional), starting at the origin of replication an moving in both directions from that point. A eukaryotic chromosome may be replicating at many points along its length at any one time.

DNA is always copied in a 5´ ⇒ 3´ direction, this makes the lagging strand to be synthesized discontinuously as short okazaki fragments.

The whole process happens at the same time in both strands in a replication fork. DNA may have different replication forks at the same time to speed up the process.