What is a cell plate, and in what stage of mitosis does it form?
The Correct Answer and Explanation is :
A cell plate is a structure that forms during cytokinesis in plant cells, which is the final stage of the cell cycle following mitosis. Unlike animal cells, which undergo cleavage furrow formation, plant cells cannot simply pinch in two due to their rigid cell walls. Instead, a cell plate is formed as a result of vesicles derived from the Golgi apparatus fusing at the center of the dividing cell.
Formation of the Cell Plate
During telophase, the last stage of mitosis, the chromosomes reach the poles of the cell, and the nuclear envelope re-forms around each set of chromosomes, creating two nuclei. Following this, the cytoplasm begins to divide, leading to cytokinesis. In plant cells, the Golgi apparatus sends small vesicles containing cell wall materials, such as pectins and hemicelluloses, to the equatorial plane of the cell. These vesicles fuse to form the cell plate, which gradually expands outward until it fuses with the existing cell wall, effectively dividing the cell into two daughter cells.
Importance of the Cell Plate
The cell plate serves several critical functions. Firstly, it ensures that each daughter cell receives its own portion of the cytoplasm and cellular organelles. Secondly, it is integral to the formation of the new cell wall, which is necessary for maintaining the structural integrity of the daughter cells. As the cell plate matures, it becomes a new cell wall, composed of cellulose, providing strength and support to the new cells.
Summary
In summary, the cell plate forms during cytokinesis, specifically during telophase in the mitotic process of plant cells. This unique mechanism allows plant cells to divide without damaging their rigid cell walls, ensuring the continuity of life and growth in plants. The formation of the cell plate is crucial for establishing two distinct daughter cells, each capable of carrying out the functions necessary for survival.