M phase

Definition

The m phase, or mitotic phase, is a stage in the cell cycle where cell division occurs, resulting in the formation of two daughter cells. This phase includes both mitosis, the process of nuclear division, and cytokinesis, the division of the cytoplasm. Proper regulation of the m phase is crucial for maintaining genetic stability and overall cellular health.

5 Must Know Facts For Your Next Test

1. The m phase is relatively short compared to other phases of the cell cycle, usually taking less than an hour to complete in rapidly dividing cells.
2. Mitosis is divided into several stages: prophase, metaphase, anaphase, and telophase, each characterized by specific events leading to cell division.
3. Cytokinesis often begins during telophase and involves the formation of a contractile ring that pinches the cell membrane to separate the two daughter cells.
4. Proper functioning of the m phase is critical for preventing genetic disorders or cancer, as errors during this phase can lead to aneuploidy or other chromosomal abnormalities.
5. Cell cycle checkpoints monitor the integrity of DNA and ensure that conditions are favorable before progressing to the m phase, helping to prevent uncontrolled cell growth.

Review Questions

• Explain how mitosis is regulated during the m phase and what happens if errors occur.
  • Mitosis is tightly regulated by various proteins and checkpoints that ensure proper chromosome alignment and segregation. If errors occur during this process, such as misaligned chromosomes, the cell can trigger checkpoint mechanisms to halt progression until the issue is resolved. Failure to correct these errors can lead to improper distribution of genetic material, resulting in conditions like aneuploidy or cancer.
• Discuss the significance of cytokinesis in relation to mitosis and how it affects cellular function.
  • Cytokinesis is crucial because it completes the process of cell division initiated by mitosis. While mitosis ensures that each daughter nucleus receives an identical set of chromosomes, cytokinesis physically separates the two new cells, allowing them to function independently. Disruptions in cytokinesis can lead to multinucleated cells or failure to divide properly, which can impair normal cellular functions and contribute to diseases.
• Evaluate the consequences of malfunctioning cell cycle checkpoints on the m phase and overall cellular health.
  • Malfunctioning cell cycle checkpoints can have dire consequences for cellular health by allowing cells with damaged DNA or other issues to enter the m phase unchecked. This can lead to aberrant cell division and potentially result in cancerous growths or genetic instability. The failure to properly regulate progression through the m phase emphasizes the importance of checkpoints in preventing disease and maintaining tissue homeostasis.

Related terms

Mitosis: The process of nuclear division during the m phase that results in two identical nuclei, each containing the same number of chromosomes as the original cell.

Cytokinesis: The division of the cytoplasm that occurs after mitosis, ultimately leading to the formation of two separate daughter cells.

Cell Cycle Checkpoints: Regulatory mechanisms in the cell cycle that ensure proper progression through each phase, including the m phase, and prevent errors such as improper DNA replication or chromosome segregation.