Cell Plate Definition
A cell plate is a structure that forms in the dividing cells of terrestrial plants and some algae. It develops in the middle plane of the cell, at the midpoint between the two groups of chromosomes in a dividing cell. The cell plate eventually forms the middle lamella of the wall between daughter cells.
The function of Cell Plate
The cell plate is a structure that forms in the cells of land plants while they are undergoing cell division. It is a disc-like structure that separates the two sets of chromosomes during cytokinesis and is involved in the formation of the cell wall between the two daughter cells following cell division.
The cell plate arises from small Golgi-derived vesicles that coalesce in a plane across the equator of the late telophase spindle to form a disk-shaped structure.
The function of the cell plate is to form a new cell wall, called the cell plate, between the two daughter cells.
The “plate” of hard sugars that forms in the middle of the parent cell will become the cell wall of future daughter cells. Cell walls serve to protect plant cells’ contents, such as their nuclei, and allow plants to have free-standing structures.
Since plants do not have skeletons like animals and are constantly growing and changing in competition to get more sunlight, it is important that individual parts of plants, such as stems and leaves, be able to stand straight against gravity on their own.
During cytokinesis in plant cells, vesicles from the Golgi apparatus carrying phospholipids needed to make the cell membrane and sugars needed to form the cell wall are delivered and assembled along a network of cytoskeleton spindle fibers that forms in the middle of the cell. This process results in forming a disk-shaped structure called a “cell plate” which eventually becomes a new cell wall between two daughter cells.
Cell Plate Formation
The “cell cycle” describes the process that cells go through, from their “birth” as new daughter cells, until they themselves are ready to split and become “parent cells” to two new daughter cells.
The formation of the cell plate takes place during the mitotic phase. In this description we will briefly describe all phases of the cell cycle to paint a complete picture, but feel free to skip to the section labeled “mitotic phase” to get a play-by-play on how the cell plate forms.
The stages of the cell cycle are divided into:
- Interphase – where the cell grows and matures
- The mitotic phase – where the cell begins working towards dividing itself
Interphase
Interphase is a stage in the cell cycle that occurs prior to cell division. It is the period when the nucleus is not dividing.
Interphase is comprised of three stages: Gap 1 (G1), S phase, and Gap 2 (G2). During G1, the cell grows in size and prepares for DNA replication. In S phase, DNA replication occurs. Finally, during G2, the cell continues to grow and prepares for mitosis or meiosis.
The duration of interphase varies depending on the type of cell and species of organism it belongs to. Most cells of adult mammals spend about 24 hours in interphase; this accounts for about 90%-96% of the total time involved in cell division. Some cells that do not divide often or ever enter a stage called G0 (Gap zero), which is either a stage separate from interphase or an extended G1.
Interphase plays an essential role in preparing cells for division. The purpose of interphase in all cell types is to prepare for cell division, which happens in a different stage of the cell cycle.
Mitotic Phase
The mitotic phase is a phase in the cell cycle of eukaryotes that involves chromosomal separation resulting in two identical sets in two nuclei. Mitosis, which is the process of cell division, consists of five morphologically distinct phases: prophase, prometaphase, metaphase, anaphase, and telophase.
During prophase, chromosomes recruit condensin and undergo a condensation process that will continue until metaphase. Cohesin is largely removed from the arms of the sister chromatids during prophase.
In most species, individual sister chromatids can be distinguished by this stage. Prometaphase is an extremely dynamic part of the cell cycle where microtubules attach to kinetochores on chromosomes and move them around.
During metaphase, chromosomes align at the center of the cell. The spindle fibers are attached to each chromosome’s kinetochore and pull it back and forth until it lines up with all other chromosomes at the center of the cell. Anaphase follows metaphase where each chromosome’s sister chromatids separate and move to opposite poles of the cell.
Telophase marks the final stage of mitosis where chromosomes reach opposite poles and begin to decondense or unravel into a stretched-out chromatin configuration. Nuclear envelopes form around the chromosomes, nucleosomes appear within the nuclear area, and cytokinesis occurs.
Mitotic phase plays a crucial role in ensuring that each daughter cell contains one exact copy of parent cell DNA. It allows cells to divide into genetically identical daughter cells for growth or repair purposes.
