Question

in mitosis, what happens during metaphase?
the nuclear membrane dissolves, the chromosomes coil, and the mitotic spindle forms.
the chromosomes line up in the middle of the cell, and the mitotic spindle fibers attach to the sister chromatids.
the microtubules shorten, pulling the sister chromatids to opposite ends of the cell.
nuclear membranes form around each set of chromosomes located at the cellular poles, and microtubule spindle fibers dissolve.

Explanation:

In metaphase of mitosis, chromosomes align at the cell's equatorial plane (middle of the cell). Mitotic spindle fibers (microtubules) attach to the kinetochores of sister chromatids. This alignment is crucial for proper segregation of genetic material in later stages.

• The first option describes prophase (nuclear membrane dissolving, chromosome coiling, spindle formation).
• The third option is anaphase (microtubules shortening, pulling chromatids apart).
• The fourth option is telophase (nuclear membranes reforming, spindle fibers dissolving).

Answer:

The chromosomes line up in the middle of the cell, and the mitotic spindle fibers attach to the sister chromatids.