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

Explanation:

Eukaryotic genomes are far larger than prokaryotic ones. Having multiple replication origins 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: multiple origins do not create more copies, they speed up the creation of one full copy.
• Option B is incorrect: all specialized cells in a eukaryote have identical DNA (barring rare mutations).
• Option C is incorrect: eukaryotes do have topoisomerase to relieve DNA unwinding tension.
• Option E is incorrect: lagging strands still exist regardless of replication origins, as they are a result of DNA polymerase's directional activity.

Answer:

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