Stages of mitosis

Interphase

The parent cell contains 23 pairs of chromosomes, and is termed DIPLOID.

During INTERPHASE, the chromosomes form a tangled mass of material in the nucleus called chromatin.

The cell spends most of its time in INTERPHASE, and in this time prepares to divide by increasing the numbers of organelles, and replicating the DNA to produce two identical copies of the genetic code.

Prophase

The cell now enters the first stage of MITOSIS (actual division), called PROPHASE.

The strands of DNA condense forming the familiar chromosome structures.

For simplicity, only four chromosomes will be shown!

The centrioles and spindle, which co-ordinate the movement of the chromosomes, migrate to the poles at either side of the cell.

Metaphase

During METAPHASE, the chromosomes line up along the centre of the spindle.

Anaphase

In ANAPHASE, the identical halves of the chromosomes (called chromatids), split and are dragged along the spindle to the poles of the cell.

The cell elongates in preparation for CYTOKINESIS, where the cytoplasm and organelles become divided between the two new “daughter” cells.

Telophase

The cell undergoes complete division or CYTOKINESIS. The nuclear membrane reforms around the chromosomes, which in turn change back into chromatin.

The two new “daughter” cells are identical to the original “parent” cell, containing a full complement of chromosomes. Both new cells enter INTERPHASE, the first stage of their own cell cycles.