Mitosis

The cell cycle There are two phases in the cell cycle: interphase, when DNA is replicated (copied) and new cell structures (e.g. mitochondria) are formed mitosis, when the cell divides in two.

This diploid cell has two sets of chromosomes – one blue and one red in each set. (Chromosomes that are the same are shown in pairs.) The copies of the chromosomes separate and each daughter cell ends up with the same number of chromosomes as the parent cell. Each chromosome is copied and the copies remain attached, forming X-shapes.

Mitosis is one kind of cell division. During mitosis: one diploid body cell divides in two, to form two diploid daughter cells daughter cells are genetically identical to the parent (original) cell.

Mitosis produces new cells during: growth, which increases the number of cells in the body repair, to replace damaged cells in tissues asexual reproduction, when offspring are formed from the division of body cells of the parent (fertilisation and gametes are not involved). As cells produced by mitosis are genetically identical, offspring produced by asexual reproduction will also be genetically identical. We say they are clones of the parent.

Cancer is the uncontrolled division (by mitosis) of body cells. In solid tissues, such as muscle and bone, cancer can produce growing lumps of cells called tumours.