CELL CYCLE

Cell cycle is a set of events that occur in order to a living cell divide in two, giving rise to a new cell with the same genetic material than the mother cell. This goes through two stages: interphase and mitosis.
G1 phase: Cell size grows due to an accumulation of nutrients. Transcription of DNA and translation of proteins are needed to make enzymes and other compounds that the next stage will need.
S phase: The DNA of the cell is replicated in this stage. The genetic material is doubled and each chromosome possesses two sister chromatids.
Mitosis (M phase): Division of the cell and nucleus by the order of prophase, metaphase, anaphase, telophase. It will end with de cytokinesis that is going to divide the cell in two.

The cell cycle

G2 phase: Cell grows because biosynthetic events happening in the cell like the formations of microtubules necessary to the mitosis for instance.
There must be some checkpoint preventing the occurrence of errors and stopping it’s proliferation. Cell cycle checkpoints are regulation mechanisms. Before entering in S phase there’s a checkpoint making sure that everything is set to DNA replication and before the M phase there’s one to prevent the damage in the DNA looking for errors. If this happens the cell may go under apoptosis preventing the passage of the error.

Bibliography:

Brown, T. A., 2002, Genomes, 2^nd ed., Oxford: Wiley-Liss.