The cell cycle comprises the events occurring between the origin of a new cell and that cell’s division. The cell cycle takes place over five phases: G₁, S, G₂, mitosis, and cytokinesis.
The transitions between phases of the cell cycle are regulated by three checkpoints: the G₁ checkpoint, the G₂ checkpoint, and the M checkpoint.

Chromosomes are pieces of DNA that have been tightly folded and wrapped around proteins.
Replicated chromosomes consist of two sister chromatids joined at the centromere.
Homologous chromosomes are different versions of the same chromosome. Homologous chromosomes have the same size, shape, and function but may have slightly different versions of most genes.
Diploid (2n) cells have two versions of every chromosome, whereas haploid (1n) cells have one version of every chromosome.

Mitosis is the method of cell division that produces two genetically identical cells. Mitosis takes place over five stages: prophase, metaphase, anaphase, telophase, and cytokinesis.
In prophase, the chromosomes condense. In metaphase, the chromosomes line up along the metaphase plate. In anaphase, the sister chromatids separate. In telophase, one nucleus forms at each end of the cell. Finally, in cytokinesis, the cytoplasm is divided and cell division is completed.

Meiosis is the process of cell division used to create gametes—sperm and egg cells. Meiosis results in the production of four haploid cells, each of which is genetically different.
In meiosis I, homologous chromosomes are separated and the chromosome number is reduced by half. In prophase I, synapsis and crossing over takes place. In metaphase I, the tetrads line up along the metaphase plate. In anaphase I, the homologous chromosomes separate. In telophase I, one nucleus forms at each end of the cell. Finally, in cytokinesis I, the cytoplasm is divided and cell division is completed.
In meiosis II, the sister chromatids are separated. Meiosis II follows the same process as mitosis.