Where does mitosis occur? Mitosis happens in the somatic cells, particularly at the nucleus. The cell goes through a series of mitotic events that culminate in the formation of two identical daughter cells.
The mitosis phases proceed in the following order of sequence: 1 prophase , 2 prometaphase, 3 metaphase , 4 anaphase , and 5 telophase. In plant cells, though, a preprophase occurs prior to prophase. In this article, 6 stages of mitosis are briefly explained.
Preprophase is a step in plant mitosis prior to prophase. During this phase, a preprophase band a transient dense microtubule band forms beneath the plasma membrane to mark the site of the plane of division and to set where the new cell wall will form during cytokinesis.
The discovery of the importance of the preprophase band in plant mitosis was based on a study on Arabidopsis plant lacking the genetic capability to produce it. The start of microtubule nucleation at the nuclear envelope also occurs during preprophase. Centrosomes organize the mitotic spindles. In plants, the nuclear membrane also called nuclear envelope serves as the microtubule-organizing center MTOC.
From chromatin, the structure condenses into a chromosome. Remember that the result after S-phase is two copies of DNA in the form of two identical chains called sister chromatids. See the schematic diagram of a chromosome below. Prometaphase is the stage of mitosis in between prophase and metaphase. The major event is the disintegration of the nuclear envelope, forming many membrane vesicles.
The same thing happens to the nucleolus; it disassembles. The disintegration of the nuclear envelope frees the chromosomes. Another important event at this stage is kinetochore formation in the centromere of the chromosome. Also, long protein filaments called kinetochore microtubules emerge from the centrosomes at the spindle pole on opposite ends of the cell.
These microtubules, then, attach to the kinetochores of the chromosomes. In metaphase, the chromosomes continue to condense. The main highlight of this stage is the alignment of the chromosomes in the equatorial plane or metaphase plate. In anaphase, the two groups of daughter chromosomes separate and move along the fibers of the central spindle to opposite poles.
In telophase, the chromosomes continue to move until two complete daughter nuclei are formed. The chromosomes de-condense into chromatin and the mitotic spindle disassembles, thus, apparently disappears. After this, cytokinesis begins.
In some references, cytokinesis is a separate process whereas in others it is a part of telophase. However, the end of telophase marks the end of the mitotic phase of the cell cycle. In animal cells, cytokinesis is marked by a cleavage furrow formation whereas in plant cells, by a cell plate forming across the center of the cytoplasm phragmoplast.
The cell plate develops into a cell wall. What is the purpose of mitosis? Why is mitosis important? Mitosis is vital for living organisms to stay alive as it is involved in vital biological processes, particularly growth and tissue repair.
Humans, for instance, rely on mitosis to produce the different cell types of the body. Without mitosis, we will have no body with intricate anatomy, to begin with.
We will remain in the zygote stage as the zygote will not progress into a plethora of organized cells with distinctive roles. In multicellular eukaryotes, the somatic cells undergo mitosis to form new cells essential for growth. When a tissue is injured, the cells divide to produce new cells that will replace lost cells. Some animals, such as starfish, have high regeneration capacity.
Nglish: Translation of mitosis for Spanish Speakers. Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! Log in Sign Up. Save Word. Definition of mitosis. First Known Use of mitosis , in the meaning defined at sense 1. Learn More About mitosis. Time Traveler for mitosis The first known use of mitosis was in See more words from the same year.
Style: MLA. Kids Definition of mitosis. Medical Definition of mitosis. The centrioles are now at opposite poles of the cell with the mitotic spindle fibres extending from them. The mitotic spindle fibres attach to each of the sister chromatids. Anaphase: The sister chromatids are then pulled apart by the mitotic spindle which pulls one chromatid to one pole and the other chromatid to the opposite pole.
Telophase: At each pole of the cell a full set of chromosomes gather together. A membrane forms around each set of chromosomes to create two new nuclei. The single cell then pinches in the middle to form two separate daughter cells each containing a full set of chromosomes within a nucleus. This process is known as cytokinesis. Related Content:. What is a stem cell? What is a cell? What is DNA?
What is a chromosome? What is a genetic disorder? What is meiosis? Mitosis versus meiosis. How helpful was this page? What's the main reason for your rating? Which of these best describes your occupation?
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