MetaphaseIn metaphase, the spindle fully develops and the chromosomes align at the metaphase plate (a plane that is equally distant from the two spindle poles).
View image of a cell in metaphase.
Changes that occur in a cell during metaphase:
- The nuclear membrane disappears completely.
- In animal cells, the two pair of centrioles align at opposite poles of the cell.
- Polar fibers (microtubules that make up the spindle fibers) continue to extend from the poles to the center of the cell.
- Chromosomes move randomly until they attach (at their kinetochores) to polar fibers from both sides of their centromeres.
- Chromosomes align at the metaphase plate at right angles to the spindle poles.
- Chromosomes are held at the metaphase plate by the equal forces of the polar fibers pushing on the centromeres of the chromosomes.