Cell Cycle

Cell cycle consists of two phases: division and the time between divisions, which is called interphase. Some kinds of cells stop dividing after they mature. These are for example: erythrocytes, nervous cells. But activity of most of them are periodical divisions (M) separated by interphases (I).

Daughter cells can be identical with the parent cell or they can differentiate. As a result of changes in the set of genes that became expressed, cell becomes functionally different from the parent one. The embryo cells strongly differentiate forming specialized tissues. Genes (DNA) remain the same, but different ones are transcribed. The differentiation of cells is controlled by special genes.

It is assumed that majority of differentiated cells do not remove unwanted genes. Exception are immune system cells in which DNA rearrangement takes place.

 

 

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