Definitions for "Cell cycle"
the sequence of phases which occurs as a cell divides.
A process in which cells reproduce. First the cell replicates its DNA and then divides into two daughter cells. The two main phases of the cell cycle are interphase and mitosis.
The somatic cell cycle of most eucaryotes is composed of four stages: S phase in which DNA synthesis and chromosome replication occurs; M phase, or mitosis, in which chromosomes segregate and cell division takes place; and "two" gap phases, G1 and G2. G1 is the phase in which cells respond to extracellular signals to commit to another round of DNA replication, or to delay entering the next cell cycle. These are cell cycle check points. Two types of delay have been identified: the delay to enter the S phase from G1, called G1 arrest, and the delay between G2 and M (mitosis), known as G2 arrest. Progression through G1 is dependent on the activity of a family of cyclin dependent kinases (Cdks) that are positively regulated by their association with a class of proteins called cyclins. Inhibition of cyclins by p21 protein causes G1 arrest and termination of DNA synthesis in the S phase. The p53 protein activates the genes for the production of the p21 protein. Diagramatic representation of cell cycle.