Mitosis 2: Metaphase

Prometaphase

The prometaphase provides a transition from prophase to metaphase. In prometaphase the nuclear envelope, which surrounds the nucleus, breaks up. The spindle now can move into the center of the cell. Kinetochores develop, which are attached to kinetochore fibers, which are linked to the chromosomes. The kinetochores then control the movements of the chromosomes. During this period the kinetochores are wildly oscillating as they try to attach themselves to one of the polar fibers. When they manage to do so the chromosome settles down.

Metaphase

[Animal cell metaphase. Notice the chromosomes are lined up along the equator of the cell. Two poles representing each daughter cell is also formed by the spindle fibers.]

In Metaphase the kinetochores that are responsible for moving the chromosomes jump begin to orientate the chromosomes. The chromosomes are orientated so that 1. each kinetochore faces the pole and 2. it moves each chromosome into a plane at the center of the spindle so that each chromosome tail is facing each other.

Continue on to Mitosis 3: Anaphase