Cytokinesis

Definition

Cytokinesis is the process during cell division where the cytoplasm of a parental cell divides into two daughter cells. This crucial phase follows mitosis or meiosis and involves various cellular structures that ensure the proper distribution of organelles and cytoplasmic content between the two new cells, linking it closely to cellular regulation, reproductive processes, and the architecture of the cytoskeleton.

5 Must Know Facts For Your Next Test

1. Cytokinesis occurs at the end of mitosis or meiosis, ensuring that each daughter cell receives an equal share of the cytoplasm and organelles.
2. In animal cells, cytokinesis is facilitated by a contractile ring made of actin and myosin filaments that pinches the cell membrane inward.
3. Plant cells undergo a different mechanism of cytokinesis involving the formation of a cell plate, which develops into a new cell wall separating the two daughter cells.
4. The regulation of cytokinesis is tightly linked to checkpoints in the cell cycle, ensuring that cells only divide when they are ready.
5. Errors during cytokinesis can lead to aneuploidy, where daughter cells end up with an abnormal number of chromosomes, impacting development and function.

Review Questions

• How does cytokinesis differ between animal and plant cells, and what are the implications of these differences?
  • Cytokinesis in animal cells involves the formation of a cleavage furrow through contraction of a contractile ring made of actin filaments. In contrast, plant cells form a cell plate that develops into a new cell wall. These differences affect how daughter cells separate; animal cells physically pinch apart while plant cells build a structure between them. Understanding these mechanisms highlights how different cellular architectures influence division processes.
• Discuss the role of microfilaments in cytokinesis and how their dynamics impact this process.
  • Microfilaments play a critical role in cytokinesis, particularly through the formation of the contractile ring in animal cells. Actin filaments provide the force necessary for membrane constriction. The dynamics of these microfilaments are regulated by various proteins that control their polymerization and depolymerization. Disruptions in microfilament function can lead to failures in cell division and result in abnormal cell behavior.
• Evaluate the importance of regulatory mechanisms during cytokinesis and their potential implications for cancer development.
  • Regulatory mechanisms during cytokinesis are essential for maintaining proper chromosome number and cell function. They involve various checkpoints that assess whether mitosis has been completed correctly before proceeding to cytokinesis. Dysregulation of these mechanisms can lead to errors such as aneuploidy, which is often observed in cancerous cells. This link underscores how understanding cytokinesis regulation can be pivotal in developing therapeutic strategies for cancer treatment.

Related terms

Mitosis: The part of the cell cycle where replicated chromosomes are separated into two new nuclei, leading up to cytokinesis.

Cleavage Furrow: The indentation that begins the process of cytokinesis in animal cells, formed by the contraction of a ring of actin filaments.

Cell Plate: The structure that forms during cytokinesis in plant cells, arising from vesicles that fuse at the center of the dividing cell.