Cytokinesis

Definition

Cytokinesis is the process that follows cell division, where the cytoplasm of a parent cell is divided into two daughter cells, completing the overall cell division. This process is crucial for ensuring that each daughter cell receives a full set of organelles and sufficient resources to function effectively after mitosis or meiosis.

5 Must Know Facts For Your Next Test

1. Cytokinesis occurs differently in animal and plant cells, with animal cells forming a cleavage furrow while plant cells create a cell plate.
2. In animal cells, the contractile ring, made up of actin and myosin, helps to constrict the cytoplasm during cytokinesis.
3. Cytokinesis is not part of mitosis or meiosis but occurs as a separate phase after these processes are completed.
4. If cytokinesis fails to occur properly, it can lead to cells with multiple nuclei or abnormal numbers of chromosomes, which can cause serious issues like cancer.
5. Timing of cytokinesis is tightly regulated to ensure it follows nuclear division, preventing any overlap that could result in cellular dysfunction.

Review Questions

• How does cytokinesis differ between animal and plant cells, and what structures are involved in each process?
  • Cytokinesis differs in animal and plant cells primarily in the mechanism and structures used for division. In animal cells, a cleavage furrow forms, driven by a contractile ring of actin and myosin that pinches the cell membrane. In contrast, plant cells form a cell plate that develops from vesicles containing cell wall materials, which eventually fuses to become the new cell wall separating the daughter cells. This difference reflects the unique structural requirements of each cell type.
• Discuss how errors during cytokinesis can lead to cellular abnormalities and their implications for health.
  • Errors during cytokinesis can result in incomplete separation of daughter cells or the formation of multinucleated cells. This can lead to an abnormal distribution of chromosomes, potentially causing genetic disorders or diseases such as cancer. Such abnormalities can affect cellular function and proliferation, making understanding cytokinesis crucial for insights into developmental biology and cancer research.
• Evaluate the regulatory mechanisms that control the timing of cytokinesis in relation to other stages of the cell cycle.
  • The regulation of cytokinesis is tightly linked to checkpoints in the cell cycle to ensure proper timing and coordination with mitosis or meiosis. Key proteins like cyclins and cyclin-dependent kinases (CDKs) control these transitions, ensuring that cytokinesis occurs only after chromosomes have been accurately separated. Disruption in these regulatory mechanisms can lead to defects in cell division and contribute to tumorigenesis, emphasizing the importance of understanding these controls in both normal physiology and disease.

Related terms

Mitosis: The phase of the cell cycle where the nucleus divides, resulting in two identical daughter nuclei.

Cleavage Furrow: The indentation that forms during cytokinesis in animal cells, leading to the separation of the two daughter cells.

Cell Plate: The structure that forms during cytokinesis in plant cells, which eventually develops into the new cell wall separating the two daughter cells.