How do eukaryotes replicate their genomes in a reasonable time frame, even though their DNA molecules are often considerably larger than those of bacteria?

Answer: All chromosomes replicate once in a cell cycle

Explanation:

DNA replication is the action of DNA polymerases synthesizing a DNA strand that is complementary to the original strand or template strand.

In eukaryotes, it is during the S phase of the cell cycle that the vast majority of DNA synthesis occur and the entire genome uncoil and divide to form two daughter cells or copies while In Bacteria, replication begins at the origin of replication, supercoiled DNA is unwound by DNA gyrase, made single-stranded by helicase, and bound by single-stranded binding protein to maintain its single-stranded state.

In Eukaryotic DNA replication. all chromosomes replicate once in a cell cycle and Replication begins at many origins along each chromosome, this is why genome replication of eukaryotes occurs faster than those of bacteteria even thouge their DNA molecules are larger than the DNA molecules of Bacteria.