Question

What is meant by cell cycle ? Discuss its various stages.

Answer 1

The cell cycle, or cell-division cycle, is the series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells.

The cell cycle consists of four distinct phases: G${}_1$ phase, S phase (synthesis), G${}_2$ phase (collectively known as interphase) and M phase (mitosis or meiosis). M phase is itself composed of two processes:

Karyokinesis, in which the cell's chromosomes are divided, and cytokinesis, in which the cell's cytoplasm divides forming two daughter cells. Activation of each phase is dependent on the proper progression and completion of the previous one. Cells that have temporarily or reversibly stopped dividing are said to have entered a state of quiescence called G${}_0$ phase.