M phase

M Phase or Mitotic Phase is a stage in the cell cycle where cell division occurs. The M phase is the final phase in the cell cycle, following the G1 phase, S phase, and G2 phase. The M phase is composed of two tightly coupled processes: mitosis, where the cell's chromosomes are divided, and cytokinesis, where the cell's cytoplasm is divided. This results in the formation of two daughter cells.

Overview

The M phase is a critical period in the cell cycle as it ensures the correct distribution of the replicated DNA to the daughter cells. The M phase is initiated by a process known as mitotic entry, which is regulated by the Mitosis-promoting factor (MPF). The MPF is a complex of the Cyclin-dependent kinase 1 (CDK1) and Cyclin B.

Mitosis

Mitosis is the process where the duplicated chromosomes are separated into two nuclei. Mitosis is divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase.

Cytokinesis

Cytokinesis is the process where the cytoplasm of the cell is divided to form two daughter cells. Cytokinesis begins in anaphase and ends in telophase, and is coordinated with mitosis.

Regulation

The M phase is tightly regulated by the cell cycle checkpoints to ensure the correct progression of the cell cycle. The spindle assembly checkpoint (SAC) is a key regulator of the M phase, ensuring that all chromosomes are correctly attached to the mitotic spindle before the cell proceeds to anaphase.

Clinical significance

Abnormalities in the M phase can lead to aneuploidy, a condition where the daughter cells have an abnormal number of chromosomes. Aneuploidy is a common feature of cancer cells.

See also

• Cell cycle
• Mitosis
• Cytokinesis
• Aneuploidy

References

M phase Resources
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