Cells and Control: Cell Division and Growth

Cell division is a vital process where a single cell divides into two identical daughter cells. This process is called mitosis.
Before a cell divides, it duplicates its DNA – this is so that each new cell will have a full set of DNA molecules.
In mitosis, the chromosomes line up at the centre of the cell and cell fibres pull them apart. The two arms of each chromosome are pulled to opposite sides of the cell.
Membranes form around each set of chromosomes becoming the nuclei of the two new cells – the nucleus has divided.
Finally, the cytoplasm and cell membrane divide to form two separate cells.
Mitosis produces two genetically identical body cells. It is used for growth, repair and asexual reproduction.
During growth, an organism’s cells divide. Cells can also become specialised, enabling them to do different jobs.
Specialisation of cells in multicellular organisms allows cells to function efficiently in a cellular capacity by performing specific tasks.
The cells in an embryo initially divide by mitosis and are capable of becoming any type of cell. These are known as embryonic stem cells.
Stem cells from adult bone marrow or from the umbilical cord of a newborn baby are not as versatile - they can only become certain types of cells.
Cell differentiation occurs in mature animals mainly for repair and replacement. In plants, it can contribute to the growth of the individual organism.
Uncontrolled cell division can lead to the formation of tumours and cancers. This is often due to certain mutations in the DNA of the cell.
Differentiation is the process by which cells become specialised. During the development of an organism, cells differentiate to become different types of cells with different roles.
Essentially, cell division and growth involve complex processes of DNA duplication, cell and cytoplasm division, and further specialisation for specific functions.