The Cell Cycle
(Timing of somatic cell division)
The whole cycle of somatic cell division typically lasts from 8 to 24 hours in humans. This is represented in the pie-chart below.
As shown in the pie-chart, the part of the cell cycle during which the nucleus of the cell is dividing (which is called mitosis) occupies approx. 10% of the time taken for the whole cycle. The cytokinesis phase takes approx. half of this time.
Most of the cell cycle is the period in which the cell is not dividing, which is called interphase.
A pie-chart is a simple way to represent this information:
Above: Typical timing of somatic cell division.
Summary of the Stages of the 'Cell Cycle' for Somatic Cells
From the page about mitosis: In all somatic cells (that is, all cells relating to the non-reproductive parts of the body = all cells except for those of the gametes) the 'cell cycle' consists of two periods:
- Interphase (also
known as 'interkinesis')
is the period in which the cell is not dividing.
This does not mean that little is happening as interphases are very active periods during which cells perform all the functions necessary for life, and also synthesise DNA (deoxyribonucleic acid) so that both of the new cells formed by the miotic phase will contain a complete copy of the original, and so have everything necessary.
- Miotic phase (M)
- when the cell is dividing.
The miotic phase of the 'cell cycle' consists of two stages:
Mitosis is the division of the cell nucleus, and is followed by:
Cytokinesis is the division of the cytoplasm of the cell into two daughter cells.
For further detail about mitosis see the diagram illustrating mitosis.