Question

part a - comparing chromosome separation in bacteria and eukaryotes
in all cells, separation of replicated chromosomes is a prerequisite for cell division. however, the mechanism of chromosome separation in bacteria is distinct from
that in eukaryotes in several ways.
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bacteria only
eukaryotes only
both bacteria and eukaryotes
replicated chromosomes separate by
attaching to some other structural
feature of the cell.
nuclear envelope fragments,
permitting chromosome separation.
two copies of the duplicated
chromosome are attached at their
centromeres before separating.
chromosomes replicate before cell
division.
chromosome separation begins at the
origin of replication on dna.
before separation, duplicated
chromosomes condense.

Explanation:

• Bacteria only: Replicated chromosomes separate by attaching to some other structural feature of the cell. Bacterial cells lack a nucleus and the complex machinery of eukaryotic cells. In bacteria, chromosome separation often involves attachment to the cell membrane or other structures as the cell elongates and divides.
• Eukaryotes only: Nuclear envelope fragments, permitting chromosome separation; Two copies of the duplicated chromosome are attached at their centromeres before separating; Before separation, duplicated chromosomes condense. Eukaryotic cells have a nucleus. During mitosis (for somatic cells) or meiosis (for gamete formation), the nuclear envelope breaks down (in prophase of mitosis or prophase I of meiosis), chromosomes condense (to facilitate proper segregation), and sister chromatids (attached at the centromere) separate (in anaphase of mitosis or anaphase II of meiosis) after the nuclear envelope has fragmented to allow spindle - microtubule interaction with chromosomes.
• Both bacteria and eukaryotes: Chromosomes replicate before cell division; Chromosome separation begins at the origin of replication on DNA. In both types of cells, for cell division to occur, the genetic material (chromosomes) must be replicated. In bacteria (which have a circular chromosome), replication starts at a single origin of replication. In eukaryotes (with linear chromosomes), there are multiple origins of replication, but the general principle that chromosome replication (DNA replication) precedes cell division holds true for both.

Answer:

• Bacteria only: Replicated chromosomes separate by attaching to some other structural feature of the cell.
• Eukaryotes only: Nuclear envelope fragments, permitting chromosome separation; Two copies of the duplicated chromosome are attached at their centromeres before separating; Before separation, duplicated chromosomes condense.
• Both bacteria and eukaryotes: Chromosomes replicate before cell division; Chromosome separation begins at the origin of replication on DNA.