Final answer:
The stage of mitosis when double-stranded chromosomes line up in the center of the cell is called Metaphase. This is a critical step for ensuring the correct distribution of chromosomes to each daughter cell during cell division.
Step-by-step explanation:
The phase of mitosis where double-stranded chromosomes line up in the center, or equator, of the cell is known as Metaphase. During this stage, chromosomes become highly condensed and align in a row along the cell's equatorial plane. This alignment is crucial for ensuring that each new daughter cell receives an identical set of chromosomes during cell division.
Stages of Mitosis
In the overall process of mitosis, Prophase is marked by the condensation of chromosomes and the formation of the mitotic spindle. During Metaphase, the chromosomes line up at the metaphase plate, with sister chromatids attached to spindle fibers emanating from opposing poles. As the cycle proceeds, Anaphase is characterized by the separation of sister chromatids as they are pulled to opposite poles. Finally, Telophase sees the new nuclei forming and the spindle fibers disappearing, completing the division.
It's important to note the distinction between mitosis and meiosis. In meiosis, we refer to Metaphase I when homologous chromosomes pair up along the metaphase plate, and Metaphase II when sister chromatids line up along the metaphase plate after the cells have gone through another round of division without chromosomal replication.