Mitosis: is nuclear division giving rise to genetically identical cells.
- Cells have a finite life: they wear out or become damaged, so they need to be replaced constantly.
- The processes of growth, repair and replacement of cells all rely on mitosis.
- Organisms that reproduce asexually also use mitosis to create more cells.
The process of mitosis:
- Each chromosome duplicates itself and is seen to be made up of two parallel strands, called chromatids.
- When the nucleus divides into two, one chromatid from each chromosomes and later they will make copies of themselves ready for the next cell division.
- The process of copying is called replication because each chromosome makes a replica of itself.
- Mitosis produces two genetically identical cells in which the number of chromosomes is the same as in the original cell.
Stem cells are those cells in the body that have retained their power of division. Examples are the basal cells of the skin, which keep dividing to make new skin cells, and cells in the red bone marrow, which constantly divide to produce the whole range of blood cells.