All phases of MITOSIS

Image: Bioenccyclopedia

The mitosis is one of the forms of cell reproduction most important and well-known. Mitosis can be summarized as the process by which the somatic cells that make up our body, duplicate and divide, creating copies of themselves. At first it may seem simple but in reality it is complex; For its study, researchers over the years have focused on the study of mitosis, definition and phases in which this process can be divided. In this lesson from a TEACHER we will see what is mitosis, definition and phases in which it can be divided, in a simple way. If you want to know more, we invite you to continue reading!

Index

1. Definition of mitosis
2. The mitosis interface
3. Prophase, the first of the phases of mitosis
4. Prometaphase and metaphase, two closely related mitotic phases
5. Anaphase: stage of fundamental mitosis
6. Telophase: the last stage of mitosis
7. Cytokinesis

Mitosis is defined as the cell division process by which genetically identical copies of a cell are generated, called a stem cell.

Mitosis is a conservative division process that, unlike the meiosis, under normal conditions, it does not create diversity. This is important for our body since mitosis is responsible for the Cell regeneration: create copies of our oldest and most degenerate cells, which are about to die, so that our tissues and organs can continue to function for many more years. Furthermore, in many single-celled organisms it is the only form of reproduction that is observed.

During the mitosis process different failures can occur. Failure to regulate mitosis can cause the cycle to speed up and certain cells divide more or less than they should. At other times, failures occur during the copying of genetic material, called point mutations, which can lead to tumors or cancers.

As you can see, mitosis is a very important process not only for the study of microorganisms, but for many other things such as study of very serious human diseases. That is why researchers have spent many years studying the different phases of the mitosis, the processes and changes that take place and the molecules and substances responsible for regulate it.

Before mitosis itself begins, the cell enters a stage called interface. During this cell phase, the cell prepares to divide and very important events occur:

• The cell stops performing its "vital functions". Just like we do our vital functions (breathing, eating, etc.), cells carry out fundamental processes for them such as generating proteins or energy to function. During the interphase and all of mitosis, these functions slow down or even pause until the mitosis is over.
• I know duplicates DNA: The two chains that make up each of the chromosomes, along with the central part that joins them, duplicate and remain partially united.
• I know duplicate cell organelles: to carry out the "vital functions" of which we spoke in the first point, cells need organelles. For the cells to be fully functional when mitosis is finished, in this phase it is copied each of the organelles: from mitochondria to ribosomes, passing through the Golgi apparatus, etc.

Image: Slideshare

The prophase is the first stage of mitosis proper. During prophase, the cell will:

• Condense its genetic material: DNA goes from a more "loose" state (called chromatin) to a more condensed or "tight" state (chromosomes). This is done to prevent damage from occurring while the cell is copying.
• I know they form the centrosomes. The centrosomes are a very important structure for subsequent phases since it will be the responsible for organizing microtubules, the structures responsible for pulling chromosomes to separate them.

Image: Glogster

Once the genetic material has condensed and the mitotic spindle has appeared, the cell passes to the prometaphase, a very short mitotic phase related to the next one, the metaphase.

During the prometaphasenuclear envelope disappears and the microtubules. Microtubules are protein structures that invade almost the entire cytoplasm of the mitotic cell and whose function is to anchor chromosomes with each other through their central part (kinetochores) or interact with microtubules that emerge from the opposite pole of the cell.

Then, in the metaphase, one of the most important events of mitosis occurs: the separation of sister chromosomes. Each one of the copies of the same chromosome separates and is placed in the center of the cell (equator). This conformation is called equatorial plate. At this point is one of the checkpoints Most importantly, and until all the sister chromosomes are separated and perfectly aligned, the metaphase will not end.

Image: Hypertext

Anaphase is a stage key code of mitosis since during it the estrangement of sister chromosomes. In the previous phase, the metaphase, the sister chromosomes had separated and aligned on the equatorial plate.

At the beginning of this phase the microtubule elongation, that is, the microtubules that separate the chromosomes and that are found in the center of the equatorial plate become longer. The chromosomes, and their respective centrosomes, are separated and each one goes to one pole of the cell.

Image: 100CIA

Telophase is the last stage of mitosis and is, according to some, an inverse stage to prophase and prometaphase. Why? Very easy, because during this stage the opposite processes to those of these two take place: chromosomes are pushed towards the ends (poles) of the cell and it goes back to form the cell envelope from the fragments left behind by the old cell envelope.

At the end of telophase, at each of the cell's poles there is: a nucleus, with its identical genetic material (if everything went well) and the organelles necessary for a cell to function.

At the same time that telophase is taking place, cytokinesis begins. Cytokinesis is a process that, although it is closely related to mitosis, is not a proper phase of it.

Cytokinesis consists of the generation of a groove in the cytoplasm of the dividing cell. This groove forms in the middle of the cell, where the metaphase plate used to be, and is now occupied by a collapsible ring. The function of this ring is to increasingly close the groove created in the center of the cell, until the two sides of the membrane come into contact and close as if they were a zipper. Finally, the groove in the center of the cell closes, the dividing stem cell is divided into two equal parts, each of which has a set of organelles of each type and a nucleus with the information genetics.

Cytokinesis is a necessary process for cell division to occur but it is not a part of mitosis since other cells with other types of cell reproduction (meiosis) also carry out this process.

Image: Curiosidario

If you want to read more articles similar to Phases of mitosis, we recommend that you enter our category of biology.

• Rodríguez-Gómez, A. by J & Frias-Vázquez, S. (2014). Mitosis and its regulation. Acta pediátrica de México, 35 (1), 55-68
• Raffino, M.E (October 11, 2019) Mitosis. Recovered from https://concepto.de/mitosis-2/
• Wikipedia (November 15, 2019). Mitosis. Recovered from https://es.wikipedia.org/wiki/Mitosis