Question

select the correct answer.
why do you think the eukaryotic dna requires multiple origins of replication?
a. multiple origins help make more copies of the same dna simultaneously
b. eukaryotic organisms have unique dna strands for each specialized cell
c. eukaryotes do not have topoisomerase, so multiple origins are created due to tension from unwinding of dna strands
d. eukaryotic dna is much larger and replication at multiple origins helps reduce the time required for whole genomes to replicate
e. multiple origins of replication ensure that there are no lagging strands and replication takes place at the same pace

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Explanation:

Eukaryotic genomes are significantly larger than prokaryotic ones. Having multiple origins of replication allows the large DNA molecule to be replicated in multiple segments at the same time, which drastically shortens the total time needed to copy the entire genome.

• Option A is incorrect because multiple origins do not create more copies, they speed up the replication of one genome.
• Option B is incorrect because all specialized cells in a eukaryote have the same DNA; cell specialization comes from gene expression, not unique DNA strands.
• Option C is incorrect because eukaryotes do have topoisomerase to relieve DNA tension during unwinding.
• Option E is incorrect because lagging strands still exist regardless of the number of replication origins, as DNA polymerase only synthesizes in the 5' to 3' direction.

Answer:

D. Eukaryotic DNA is much larger and replication at multiple origins helps reduce the time required for whole genomes to replicate.