In eukaryotic cells, replication often initiates at many origins of replication. Which statement is true?

• A. One Origin of Replication
• B. Many Origins of Replication
• C. No Origins of Replication
• D. Random Origins Appear During Replication

Answer: (B)

In eukaryotes, DNA replication uses many origins of replication scattered along the chromosomes. Before S phase, the cell licenses potential origins by binding the origin recognition complex and loading helicases, so these sites are prepared to start replication. When S phase begins, a subset of these licensed origins fires, producing replication forks that move outward in opposite directions. Having multiple origins lets replication proceed in parallel across different genome regions, speeding up the overall process and ensuring the entire genome is copied in a reasonable time. So the true statement is that there are many origins of replication.

Origins aren’t created randomly during replication; they’re established and licensed in advance, and only some fire during S phase. The idea of a single origin is typically associated with simpler organisms like many bacteria, not with eukaryotic genomes. The notion that no origins exist is incorrect, since replication requires defined starting points.