Search results
Results from the WOW.Com Content Network
Once pollination occurs, the tube cell grows in size and if the male gametophyte is only 2 cells at this stage, the single sperm cell undergoes mitosis to create a second sperm cell. [21] Just like in gymnosperms, the tube cell in angiosperms obtains nutrients from the sporophytic tissue, and may branch out into the pistil tissue or grow ...
It is the biological process of gametogenesis during which cells that are haploid or diploid divide to create other cells. It can take place either through mitotic or meiotic division of diploid gametocytes into different cells depending on an organism's biological life cycle. For instance, gametophytes in plants undergo mitosis to produce gametes.
The different stages of mitosis altogether define the mitotic phase (M phase) of a cell cycle—the division of the mother cell into two daughter cells genetically identical to each other. [ 3 ] The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next.
Sperm cells are derived by mitosis of the generative cell during pollen tube elongation. The vegetative cell is responsible for pollen tube development. Double-strand breaks in DNA that arise appear to be efficiently repaired in the generative cell, but not in the vegetative cell, during the transport process to the female gametophyte. [32]
However, the parent sporophyte may be monoecious, producing both male and female gametophytes or dioecious, producing gametophytes of one gender only. Seed plant gametophytes are extremely reduced in size; the archegonium consists only of a small number of cells, and the entire male gametophyte may be represented by only two cells. [27]
The different stages of mitosis all together define the M phase of an animal cell cycle—the division of the mother cell into two genetically identical daughter cells. [3] To ensure proper progression through the cell cycle, DNA damage is detected and repaired at various checkpoints throughout the cycle.
Only one of the four resulting megaspores survives. This megaspore undergoes three rounds of mitosis, resulting in seven cells with eight haploid nuclei (the central cell has two nuclei, called the polar nuclei). The lower end of the embryonic sac consists of the haploid egg cell positioned in the middle of two other haploid cells, called ...
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.