Reproduction is one of the most intricate and complex phenomena occurring in species, which is why examining it further will contribute tremendously to the understanding of cells development and the functioning of living organisms, in general. Mitosis is one of the two methods that are used on a cellular level for reproduction (Yanagida 3). Specifically, according to Yanagida, mitosis is “a morphological (cell structural) event, and a number of visible cell structural mitotic markers have been proposed, such as nuclear membrane disassembly, chromosome condensation, spindle formation, kinetochore microtubule formation, etc.” (p. 2).
By studying the concept of mitosis closer and understanding in greater detail what occurs on the cellular and molecular levels within cells during it, one will be able to approach a more accurate interpretation of the genetic makeup of different species.
The first step of mitosis can be described as the preparation for the following cell division. Mitosis starts with the stage known as prophase, which implies having chromosomes organized with the help of condensing (Saha and Begum 75). As a rule, at the specified stage of mitosis, cohesin contained in the sister chromasin arms is removed from the specified location so that individual sister chromatids could be successfully resolved (Li et al. 2596). Afterward, the preparation for the second stage of mitosis begins.
During the second phase, which is known as prometaphase, the actual cell division process is set into motion. Namely, at the moment of prometaphase, the nuclear envelope fragmentation occurs. Thus, the cell is split into tiny vessels that will serve as the building blocks for the daughter cells (Ikeda and Tanaka 1126). The specified stage of mitosis occurs at a particularly fast pace since it requires microtubules to assemble and dissipate when being produced in centrosomes (Zhang et al. 158).
Microtubules seek the opportunity to reattach as they undergo the process of assembling and disassembling, seeking kinetochores that can provide attachment sites to them (Ikeda and Tanaka 1127). Furthermore, as microtubules continue to grow, they stretch and expand the chromosomes, causing pole-directed forces to stabilize within the cells (Zhang et al. 159). As a result, when the prometaphase, chromosomes gain pole orientation (Ikeda and Tanaka 1127). The described change prepares the cells for the third stage of mitosis.
Next, a crucial change in the chromosomes of a cell occurs. During metaphase, which is the third stage of mitosis, chromosomes are arranged in the most compact manner possible (Guo et al. 1128). As the centromeres of a cell align among the spindle equator, the genetic material of the maternal cell is duplicated, which allows for the two daughter cells to emerge (Orr et al. 1086). When compared to the rest of the stages of mitosis, metaphase is, perhaps, the most peculiar one since it involves the process of splitting the genetic material into two identical sets (Orr et al. 1086). Partaking in a metaphorical tug of war, the kinetochores, or protein strands, allow for the duplication process to launch.
At the specified stage, the phenomenon known as the metaphase checkpoint occurs (Guo et al. 1128). The described stage is particularly important in the mitosis process since at the specified point in time, the cells that will divide are identified. Thus, as soon as all of the kinetochores are properly attached and aligned, the cells enter the fourth stage of the process.
The fourth phase of mitosis also deserves a separate description as a crucial part of the process. During the fourth phase, the cells that cells with properly aligned spindles enter the state of anaphase, during which sister chromatids are divided and set apart from each other. The process in question is known as anaphase and is set into motion as a result of the degradation of the cohesin molecules (Yanagida 2). The anaphase process leads to the production of two essential types of change, namely, the shortening of the kinetochore microtubules and their further motion toward the spindle poles (Wall et al. 3).
The fifth and the final stage of mitosis termed as the telophase implies the reformation of the membrane and the decondensation of the chromosomes. Finally, the cytokinesis ensues causing the eventual emergence of daughter cells (Li 2954). Ending with cytokinesis, namely, the process of cytoplasm being split to form two daughter cells, the specified stage ends with the emergence of two cells with identical genetic makeup (Abramo et al. 1395). Thus, mitosis ends, showing that replication of cells with the resulting production of two identical ones is a natural process within tissues in the human body, as well as in some organisms. Overall, observing mitosis helps to discover the intricate details of cell reproduction, thus, developing a clear idea of the genetic material transfer.
The exploration of the mitosis process is particularly useful from a biological perspective since it guides one’s understanding of the key changes occurring during it on biological and molecular levels, therefore, gaining a better idea of the genetic alterations within cells and the functions of specific chromosomes. Therefore, the phenomenon of mitosis is worth considering as an illustration of the changes within cells during the described reproduction method. With the understanding of mitosis, one will develop a clear idea of the key strategies of transferring genetic material from a maternal cell to the daughter cells.
Works Cited
Abramo, Kristin, et al. “A Chromosome Folding Intermediate at the Condensin-to-Cohesin Transition during Telophase.” Nature Cell Biology, vol. 21, no. 11, 2019, pp. 1393-1402.
Guo, Ao, et al. “Single-Cell Dynamic Analysis of Mitosis in Haploid Embryonic Stem Cells Shows the Prolonged Metaphase and Its Association with Self-Diploidization.” Stem Cell Reports, vol. 8, no. 5, 2017, pp. 1124-1134.
Ikeda, Masanori, and Kozo Tanaka. “Plk1 Bound to Bub1 Contributes to Spindle Assembly Checkpoint Activity During Mitosis.” Scientific Reports, vol. 7, no. 1, 2017, pp. 1-15.
Li, Xing, Fan Yang, and Boris Rubinsky. “A Theoretical Study on the Biophysical Mechanisms by Which Tumor Treating Fields Affect Tumor Cells during Mitosis.” IEEE Transactions on Biomedical Engineering, vol. 67, no. 9, 2020, pp. 2594-2602.
Orr, Bernardo, and Helder Maiato. “No Chromosome Left Behind: The Importance of Metaphase Alignment for Mitotic Fidelity.” The Journal of Cell Biology, vol. 218, no. 4, 2019, p. 1086.
Saha, Susmita, and Kazi Nahida Begum. “A Comparative Analysis on Mitotic Interphase and Prophase among Twelve Varieties of Brassica L. from Bangladesh: Brassicaceae.” International Journal of Biosciences, vol. 17, 2020, pp. 73-82.
Wall, Richard J., et al. “Plasmodium APC3 Mediates Chromosome Condensation and Cytokinesis during Atypical Mitosis in Male Gametogenesis.” Scientific Reports, vol. 8, no. 1, 2018, pp. 1-10.
Yanagida, Mitsuhiro. “The Role of Model Organisms in the History of Mitosis Research.” Cold Spring Harbor Perspectives in Biology, vol. 6, no. 9, 2014, pp. 1-15.
Zhang, Haoyue, et al. “Chromatin Structure Dynamics during the Mitosis-to-G1 Phase Transition.” Nature, vol. 576, no. 7785, 2019, pp. 158-162.