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When plant cells are in a hypertonic solution, the flexible cell membrane pulls away from the rigid cell wall, but remains joined to the cell wall at points called plasmodesmata. The cells often take on the appearance of a pincushion, and the plasmodesmata almost cease to function because they become constricted, a condition known as ...
Schematic karyogram of the human chromosomes, showing their usual state in the G 0 and G 1 phase of the cell cycle. At top center it also shows the chromosome 3 pair in metaphase (annotated as "Meta."), which takes place after having undergone DNA synthesis which occurs in the S phase (annotated as S) of the cell cycle.
In both animal and plant cells, cell division is also driven by vesicles derived from the Golgi apparatus, which move along microtubules to the middle of the cell. [56] In plants, this structure coalesces into a cell plate at the center of the phragmoplast and develops into a cell wall
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
In general, mitosis (division of the nucleus) is preceded by the S stage of interphase (during which the DNA replication occurs) and is followed by telophase and cytokinesis; which divides the cytoplasm, organelles, and cell membrane of one cell into two new cells containing roughly equal shares of these cellular components.
Plants with cells in this condition wilt. After plasmolysis the gap between the cell wall and the cell membrane in a plant cell is filled with hypertonic solution. This is because as the solution surrounding the cell is hypertonic, exosmosis takes place and the space between the cell wall and cytoplasm is filled with solutes, as most of the ...
Therefore, the accurate control of cell division planes and placement of the future cell wall in plant cells is crucial for the correct architecture of plant tissues and organs. The preprophase stage of somatic plant cell mitosis serves to establish the precise location of the division plane and future cell wall before the cell enters prophase.
Another form of mitosis occurs in tissues such as liver and skeletal muscle; it omits cytokinesis, thereby yielding multinucleate cells (see syncytium). Plant cytokinesis differs from animal cytokinesis, partly because of the rigidity of plant cell walls. Instead of plant cells forming a cleavage furrow such as develops between animal daughter ...