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Comparing Chromosome Separation in Bacteria and Eukaryotes: Mastering Biology Answers

Both cell types copy and partition DNA before division, but the introductory bacterial model begins segregation near the replication origin, while eukaryotic mitosis uses condensed sister chromatids, centromeres, kinetochores, and a spindle.

Question

Sort each statement into **Bacteria only**, **Eukaryotes only**, or **Both bacteria and eukaryotes**.- Chromosomes replicate before cell division.- Replicated chromosomes separate by attaching to some other structural feature of the cell.- Chromosome separation begins at the origin of replication.- Duplicated chromosomes condense before separation.- The nuclear envelope fragments, permitting chromosome separation.- The two duplicated chromosome copies are attached at their centromeres before separation.

Correct classification

Bacteria only

  • Chromosome separation begins at the origin of replication. In the introductory bacterial model, the origin region is duplicated first, and the two origin copies begin moving apart while replication continues.

Eukaryotes only

  • Duplicated chromosomes condense before separation. Chromatin compacts into the visible mitotic chromosomes used in the course model.
  • The nuclear envelope fragments, permitting chromosome separation. In typical open mitosis, nuclear-envelope breakdown gives spindle microtubules access to chromosomes.
  • The two duplicated chromosome copies are attached at their centromeres before separation. Sister chromatids remain joined until the separation step; kinetochores assemble at the centromere region.

Both bacteria and eukaryotes

  • Chromosomes replicate before cell division. Each daughter cell needs a complete genome copy.
  • Replicated chromosomes separate by attaching to another cellular structure. Bacteria couple replicated DNA to segregation and cell-organization machinery, while eukaryotic chromosomes attach through kinetochores to the spindle.

The shared goal is accurate genome partitioning, but the visible machinery differs because a typical bacterium lacks a nucleus and a mitotic spindle, whereas a eukaryotic cell packages multiple linear chromosomes for mitosis.

Evidence boundary

This classification uses the Mastering Biology introductory model of a typical bacterium and open eukaryotic mitosis. Bacterial segregation mechanisms vary among species, and some eukaryotes undergo closed mitosis without complete nuclear-envelope breakdown.

Sources

These references support the concepts and methods used in the explanation above.

Chromosome Separation in Bacteria and Eukaryotes Answers | Verla