During which phase do chromosomes align at the cell's equator?

During which phase do chromosomes align at the cell's equator?

• A. Prophase
• B. Anaphase
• C. Metaphase
• D. Telophase

Answer: (C)

During metaphase the chromosomes line up along the middle of the cell, at the metaphase plate. This alignment happens because spindle fibers attach to the kinetochores of each chromosome and exert balanced forces from opposite poles, creating tension that positions all chromosomes in a single plane between the two ends of the cell. This arrangement ensures that when the next phase begins, sister chromatids can be pulled apart evenly to opposite sides. Before this stage, chromosomes condense and the nuclear envelope breaks down in prophase, but they aren’t yet arranged at the center. After alignment, during the next phase, the chromatids are pulled apart toward the poles, and later the nuclear envelope reforms and chromosomes de-condense.

During metaphase the chromosomes line up along the middle of the cell, at the metaphase plate. This alignment happens because spindle fibers attach to the kinetochores of each chromosome and exert balanced forces from opposite poles, creating tension that positions all chromosomes in a single plane between the two ends of the cell. This arrangement ensures that when the next phase begins, sister chromatids can be pulled apart evenly to opposite sides.

Before this stage, chromosomes condense and the nuclear envelope breaks down in prophase, but they aren’t yet arranged at the center. After alignment, during the next phase, the chromatids are pulled apart toward the poles, and later the nuclear envelope reforms and chromosomes de-condense.