Cytokinesis

Definition

Cytokinesis is the process during cell division where the cytoplasm of a parental cell is divided into two daughter cells. This crucial phase follows mitosis and ensures that each new cell receives the necessary organelles and cytoplasmic components to function properly. It plays a key role in maintaining cellular integrity and is essential for the growth, development, and repair of tissues.

5 Must Know Facts For Your Next Test

1. Cytokinesis occurs differently in plant and animal cells; in animal cells, it involves the formation of a cleavage furrow, while in plant cells, a cell plate forms to divide the cells.
2. The timing of cytokinesis is critical, as it must happen after mitosis to ensure that each daughter cell inherits the correct number of chromosomes.
3. Cytokinesis can be influenced by various factors including cell size, nutrient availability, and external signals from neighboring cells.
4. In some cases, if cytokinesis does not occur properly, it can lead to multinucleated cells or abnormal cell growth, which may contribute to diseases such as cancer.
5. The proteins involved in cytokinesis include actin and myosin, which help contract the cleavage furrow in animal cells and play a role in forming the cell plate in plant cells.

Review Questions

• How does cytokinesis differ between plant and animal cells, and what are the implications of these differences?
  • Cytokinesis differs between plant and animal cells primarily in the mechanism used to divide the cytoplasm. In animal cells, cytokinesis occurs through the formation of a cleavage furrow that pinches the cell into two separate daughter cells. In contrast, plant cells form a cell plate that eventually develops into a new cell wall. These differences are significant because they reflect how each cell type maintains structural integrity while dividing, which is essential for proper growth and development.
• Discuss the role of key proteins in cytokinesis and how their malfunction might affect cell division.
  • Key proteins like actin and myosin play critical roles in cytokinesis by facilitating the contraction of the cleavage furrow in animal cells and helping to construct the cell plate in plant cells. If these proteins malfunction or are insufficient, cytokinesis may be incomplete or fail altogether. This can lead to issues such as multinucleation or improper distribution of cellular components, which may result in abnormal growth patterns or contribute to diseases such as cancer.
• Evaluate how external factors such as nutrient availability can influence cytokinesis and overall cell division processes.
  • External factors like nutrient availability significantly influence cytokinesis and overall cell division processes. For instance, when nutrients are scarce, cells may delay division until conditions improve, ensuring that daughter cells have enough resources for survival and growth. Additionally, signaling pathways that respond to environmental cues can either promote or inhibit cytokinesis based on cellular conditions. This adaptability is crucial for maintaining tissue homeostasis and can also have implications in developmental biology and cancer research.

Related terms

Mitosis: The process of nuclear division that results in two identical daughter nuclei, typically followed by cytokinesis.

Cell Cycle: The series of phases that a cell goes through from one division to the next, including interphase and the mitotic phase.

Cleavage Furrow: The indentation that begins to form in the cell membrane during cytokinesis in animal cells, leading to the separation of the daughter cells.