Which statement correctly contrasts prokaryotic and eukaryotic DNA replication?

Which statement correctly contrasts prokaryotic and eukaryotic DNA replication?

• A. Prokaryotes have linear chromosomes and a nucleus
• B. Eukaryotes replicate only once per cell cycle
• C. Prokaryotes have a single circular chromosome with a single origin, while eukaryotes have many linear chromosomes with many origins
• D. Eukaryotes replicate in the cytoplasm

Answer: (C)

The concept here contrasts how DNA is organized and copied in the two cell types. Prokaryotes typically have a single circular chromosome located in the cytoplasm, and replication starts at a single origin, proceeding bidirectionally around the circle. Eukaryotes, on the other hand, have many linear chromosomes housed in the nucleus, and each chromosome contains multiple origins of replication so that the entire genome can be copied efficiently within the S phase. That combination of a single circular genome in the cytoplasm versus many linear chromosomes in the nucleus with multiple origins is why this statement is the correct contrast. The other options misstate basic features—prokaryotes do not have a nucleus and do not usually have linear chromosomes; eukaryotes do not replicate in the cytoplasm; and the key distinction is not merely “how often” replication occurs per cycle but how many origins enable replication of a larger genome.

The concept here contrasts how DNA is organized and copied in the two cell types. Prokaryotes typically have a single circular chromosome located in the cytoplasm, and replication starts at a single origin, proceeding bidirectionally around the circle. Eukaryotes, on the other hand, have many linear chromosomes housed in the nucleus, and each chromosome contains multiple origins of replication so that the entire genome can be copied efficiently within the S phase. That combination of a single circular genome in the cytoplasm versus many linear chromosomes in the nucleus with multiple origins is why this statement is the correct contrast. The other options misstate basic features—prokaryotes do not have a nucleus and do not usually have linear chromosomes; eukaryotes do not replicate in the cytoplasm; and the key distinction is not merely “how often” replication occurs per cycle but how many origins enable replication of a larger genome.