Define cytokinesis Select any of the following which describe or define cytokinesis accurately. Involves the replication of DNA Precedes nuclear division Involves a cleavage furrow and a cell plate in all cells A phase of the cell cycle during which the cytoplasm divides Involves a cell plate in plant cells Follows nuclear division Involves a cleavage furrow in animal cells Only occurs in animal cells Darnt
The Correct Answer and Explanation is :
Correct Answers:
- A phase of the cell cycle during which the cytoplasm divides
- Involves a cell plate in plant cells
- Follows nuclear division
- Involves a cleavage furrow in animal cells
Explanation:
Cytokinesis is the process in which the cytoplasm of a single eukaryotic cell divides to form two daughter cells. It occurs after mitosis or meiosis and ensures that each daughter cell receives the necessary cellular components. It is a crucial step in the cell cycle, typically occurring in the M phase following nuclear division (mitosis or meiosis).
Cytokinesis does not involve DNA replication, as DNA replication occurs during the S phase of the cell cycle, before mitosis begins. It also does not precede nuclear division; rather, it occurs after nuclear division, ensuring that each nucleus is enclosed in its own new cell.
The mechanism of cytokinesis differs between animal and plant cells:
- In animal cells, cytokinesis occurs through the formation of a cleavage furrow. This furrow is created by a contractile ring composed of actin and myosin filaments, which tighten around the center of the cell and pinch it into two separate daughter cells.
- In plant cells, a cell plate forms instead of a cleavage furrow. Since plant cells have a rigid cell wall, they cannot simply constrict. Instead, vesicles from the Golgi apparatus fuse at the center of the dividing cell, forming a cell plate, which eventually develops into a new cell wall, dividing the two daughter cells.
It is incorrect to say that cytokinesis only occurs in animal cells, as it occurs in both animal and plant cells, albeit through different mechanisms. Without cytokinesis, cells would contain multiple nuclei within a single cytoplasm, which can be seen in certain specialized cells but is not the norm for most organisms.