Mitosis and the cell cycleSpec 4.1.2.2
In short
The cell cycle is the series of stages in which a cell divides to form two genetically identical cells. First the cell grows, increases its sub-cellular structures and replicates its DNA. In mitosis, one set of chromosomes is pulled to each end of the cell and the nucleus divides. Finally the cytoplasm and cell membranes divide.
Cells divide in a series of stages called the cell cycle. During the cell cycle the genetic material is doubled and then divided into two identical cells. There are three overall stages.
- Growth and DNA replication. Before a cell can divide it needs to grow and increase the number of sub-cellular structures such as ribosomes and mitochondria. The DNA replicates to form two copies of each chromosome.
- Mitosis. One set of chromosomes is pulled to each end of the cell and the nucleus divides.
- Cytoplasm and cell membranes divide. Finally the cytoplasm and cell membranes divide to form two identical cells.
(opens full size in a new tab)You need to understand the three overall stages but you do not need to know the different phases of the mitosis stage.
Cell division by mitosis is important in the growth and development of multicellular organisms. In mature animals, cell division is mainly restricted to repair and replacement.
Recognising mitosis in context
You should be able to recognise and describe situations in given contexts where mitosis is occurring. Look for the production of new, genetically identical cells.
- An embryo or seedling growing in size.
- The tip of a root or shoot lengthening.
- A cut healing, as new skin cells replace the damaged ones.
- Worn out cells being replaced.
Mitosis makes two cells that are genetically identical to each other and to the parent cell. Do not say 'different' or 'half the chromosomes'.
Written and checked against the AQA GCSE Combined Science (8464) specification · Updated October 2026