How To Explain Mitosis To Children
After fertilization, the newly formed embryonic cell must originate all the others until a complete organism is created. Once formed, the embryonic cell must grow and, during this process, the cells of the body mature, multiply and die. But how do cells reproduce? In this article we will see how to explain mitosis to kids.
What is mitosis?
Mitosis is the process by which cells reproduce. It is one of the 2 stages that make up the cell cycle and takes place after the duplication of the genetic material. As a result, two daughter cells equal to the stem cell are obtained.
Mitosis occurs in somatic cells, or in any cell in the body that is not a gamete. Gametes are formed by another process called meiosis, which is the opposite process to cell multiplication, namely a division.
The cells in our body resort to mitosis when they need to grow or repair a wound caused to a tissue, bone or organ. But how does the mitosis process develop?
The stages of mitosis explained to children
In order for the cells to reproduce, an earlier phase is required, the Interphase, during which the genetic material is duplicated and the cell passes from 23 pairs of chromosomes to 46. Furthermore, some organelles, such as centrioles, duplicate themselves, while others they disappear and then, within a few hours, are synthesized again.
In this way, everything is ready for the cell to enter mitosis. The process takes place in 4 clearly differentiated phases: Prophase, Metaphase, Anaphase and Telophase.
Phase 1: the Prophase
- The genetic material of the cells begins to condense and chromosomes appear.
- The nuclear membrane destabilizes and disappears.
- The centrioles, one of the most important organelles during this process, duplicate and begin to travel to the cell poles.
Phase 2: the Metaphase
To better understand this phase, it is necessary to imagine the cell as a sphere similar to the Earth.
- In the poles we will have the centrioles, from which fibers that resemble the lines of latitude of the Earth will begin to grow. This structure is called a mitotic spindle.
- The chromosomes directed by the fibers of this spindle go to the equator of the cells, and align there forming the equatorial plate.
Phase 3: the Anaphase
- Once the chromosomes are aligned, the centrioles begin to collect the fibers of the mitotic spindle.
- This causes the chromosomes trapped in the fibers – shaped like an 8-armed spider – to split in two and be dragged towards the poles. Now, each chromosome has two chromatics with 4 arms again.
Phase 4: the Telophase
- Once the chromosomes have been placed on opposite poles of the cell, they begin to divide.
- At the same time, the cell will again form the nuclear membrane around them from the fibers of the centrioles.
The final stage of mitosis: cytokinesis
At this point, all that remains is to physically divide the stem cell to originate the two daughter cells. The process of cell multiplication, ultimately, is a division, so the stem cell disappears into two daughter cells.
The resulting daughter cells will be genetically the same as the mother and will contain the same organelles. The function they develop will depend on the genes expressed and the degree of maturation of the original cell.
What happens if mistakes are made during mitosis?
The errors that can occur during the mitosis process are very few, as the cell has a strict quality system and stops the production process only if the error is fatal.
This fact does not mean that errors cannot occur, especially in the first divisions of the zygote. If this error cannot be repaired and the cell cycle continues, the anomaly can go from imperceptible to carcinogenic.
One of the most frequent errors is the nondisjunction of chromosomes, in which one of the homologous chromosomes does not separate correctly during anaphase. As a result, we get a daughter cell with three chromosomes, trisomy, and the other with only one, aneuploidy.
On other occasions, the chromosomes can be damaged, breaking one of their arms and causing a deletion, or a fragment can be incorporated into a chromosome from another pair, causing a translocation. It can also happen that the fragment is integrated in the reverse direction on the same chromosome, causing an inversion.
And finally…
To finish this article on how to explain mitosis to children, here is a curiosity. The process of mitosis was first described in 1848 by the German botanist Wilhelm Hofmeister, who was studying the embryonic development of plants. However, the actual discovery is attributed to Walther Flemming, as he was the first to discover the division of chromosomes.
-Alexander Graham Bell-
