Question 57

DNA is condensed and then sister chromatids are organized along the midline of the cell.

During the transition from prophase to metaphase in mitosis, DNA condenses into visible chromosomes, and sister chromatids align at the cell's equatorial plane, preparing for separation.

A) Chromatids are separated and isolated into separate daughter nuclei.

This option is incorrect because chromatids are not separated until the anaphase stage of mitosis. During metaphase, they are aligned in the middle of the cell, not isolated into daughter nuclei.

B) Chromosomes are uncondensed and arranged randomly throughout the cell.

This choice is also incorrect as it misrepresents the state of chromosomes during metaphase. By this stage, chromosomes are fully condensed and organized along the cell's equator, not uncondensed or randomly arranged.

C) Chromosomes are aligned along the center of the cell and then pulled apart into separate chromatids.

While this statement includes the alignment of chromosomes along the center, it inaccurately conflates events from metaphase and anaphase. The actual pulling apart of sister chromatids occurs in anaphase, not during the transition from prophase to metaphase.

D) DNA is condensed and then sister chromatids are organized along the midline of the cell.

This option accurately describes the events that occur during the transition from prophase to metaphase. During this stage, the chromosomes are indeed condensed and aligned at the cell's equatorial plane, preparing for the next phase of mitosis.

Conclusion

In summary, the correct answer, D, accurately captures the key events that occur as cells transition from prophase to metaphase in mitosis. The other options fail to correctly describe this transition, either by misplacing events in the mitotic process or by providing incorrect descriptions of the chromosome state during metaphase.