Answers. Best Answer: Mitosis is the process of cell division. The cell equator, or equatorial plate, is when the nucleus has broken down, and the chromosomes are lengthening, and forming a line in the middle of the cell. This happend during Metaphase.This line is called the cell equator.he cell equator, or equatorial plate, is when the nucleus has broken down, and the chromosomes are lengthening, and forming a line in the middle of the cell. This happend during Metaphase.