What phase of mitosis is characterized by chromosomes lining up across the center of the cell?

During mitosis, the phase where chromosomes align at the center of the cell is called metaphase. This critical step follows prophase, where the chromosomes condense and become visible, and is marked by the formation of the mitotic spindle, which attaches to the centromeres of the chromosomes.

In metaphase, each chromosome is lined up in the middle of the cell, also referred to as the metaphase plate. This arrangement is crucial because it ensures that when the chromosomes are pulled apart during the next phase, anaphase, each daughter cell will receive an identical set of chromosomes. The alignment is facilitated by the spindle fibers, which pull on the chromosomes to ensure they are evenly distributed.

Understanding the significance of metaphase highlights how proper alignment of chromosomes is vital for the accuracy of cell division, and any errors in this alignment can lead to genetic abnormalities in the resulting daughter cells.