The life cycle of a cell is called the cell cycle. The cycle progresses from a new cell to one that grows, develops, carries out life processes and ultimately will divide again once it is mature. A mature cell by definition is differentiated or specialized to be a specific type of cell in the body unlike a stem cell which is undifferentiated. An example of a differentiated cell is a muscle cell or a nerve cell.
Depending on the type of cell, it may frequently divide like a skin cell or not divide after becoming mature like a nerve cell.
There are specific controls for the cell cycle which include different chemical signals that must be present to proceed to each stage of the cell cycle. There are checkpoints which allow the cycle to go from one stage to the next. Signals provided by specific chemicals at the correct time allow the cycle to function in a coordinated and organized way.
The cell cycle has the G1, S, G2 and M phases. During G1, a signal is required to cause the cell to proceed through the cycle to the M phase where it will eventually divide to form two daughter cells. If a signal is not present, the cell switches off to a phase where it doesn't divide, known as Go (G naught).
During G1 the cell grows and manufactures organelles. During the S phase, the chromosomes are duplicated to insure a complete set will be provided to each daughter cell at the end of the cell cycle. During G2 the cell grows some more.
Eventually, the cell enters the M or mitosis phase. It will divide to become two daughter cells after cytokinesis occurs. That is, when the cytoplasm is divided into the two daughter cells. These two new cells will enter into the G1 phase of the cell cycle and will someday divide once they grow and become mature.
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