Background to the Mitotic Cell Cycle
Mitotic can be defined as the type of eukaryotic cell division which creates two daughter cells with similar genetic element as their parent cell. Cell behave almost the same way when the replicate and therefore, chromosome replicate the same during S phase to make sure that each daughter cell formed as a copy of chromosome. However, the cell cycle is the series of stages or event s which occur in a cell to cause its division and duplication of the cell DNA as well. However, the mitotic cell cycle is composed of metaphase, anaphase, prophase, Cytokinesis and telophase. According to Larsen (2012, p.10), each of these phases is essential to the mitotic cell cycle and at each stage there is an event which occurs to facilitates the formation of daughter cells. For instance, at metaphase the chromosome align themselves al;ong the plate of metaphase of the spindle of apparatus (Larsen, 2012, p. 12).
The Prophase stage is important to the cell cycle since it is the phase where the nuclear membrane breaks into pieces to form several small nucleolus and vesicles disintegrates. This is the phase whereby mitotic spindle is formed for mitotic cell duplication which allows the mitotic to form tow daughter cells. As stated by Lersen (2012), the cell cycle us essential because it prevents the division of the cell when it is not required to occur and it makes the division of the cell to take place when it is needed. Therefore, the cell division is essential to cell to grown and divide in multicellur organism. The mitosis is important because it ensures that there is continuity of genetic by making sure that it creates a copy of DNA. It makes sure that the DNA is taken by carried by keeping the same number of chromosome is carried from one cell to others. Therefore, the mitosis takes place in the skin, bones and muscles and immediately the mitosis is complete a daughter cell is formed.
Studies have established that phases of the cell cycle can take different time to complete a complete cycle. Bettitta, Yigin and Kiriaki (2015) noted that normally human cell has a 24 hours of cycle time and the G1 phase is likely to take about eleven hours, G2 phase will take about four (4) hours, S phase eight (8) hours and M phase is also likely to take about one (1) hour. However, other types of cell can divide very rapidly though yeasts can go through the all four stages of cell division. The most important thing is that chromosome condenses during mitotic cell cycle. The shape and the degree of compaction of chromosomes undergo several changes at the interphase immediate it enters the mitosis which further condense and individualize to form chromosome (Buttitta, Yiqin, & Kiriaki, 2015).
Figure 1: chromatic structure during mitosis
According to Antomin and Heinz (2016), once the chromosome is segregated by the spindle, the chromatin is reignited to reform its interphase structure fit or which can be competent for DNA transcription and replication. The molecular mechanism of mitotic then condense and decodense to reform its interphase structure (Antonin & Heinz, 2016). It is proper to note that chromosome replicate during S phase and therefore, it changes it structure when it condense and decondense to regain a new shape.
The experiment was completed in the laboratory using toluidine blue and dye that binds to DNA to give accurate result. The experience result indicates that the cell of untreated root has the lowest number of mitotic index. Though untreated root has the highest number of cells at the interphase and the cells continue to reduce as the cells of untreated root goes through the cell cycle. From the result it seems Organophosphate treated roots have the highest mitotic index of 7.9, followed by Babybio treated roots with a mitotic index of 7.2. This means that the cell takes more time at interphase stage compared to others like Metaphase and Telophase.
|Cell in||Cell in||Cell in||Cell in||Cell in||Mitotic|
|Manure Treated root||1800||51||27||37||9||6.4|
|Organophosphate treated roots||1210||42||20||31||10||7.9|
|Babybio treated Roots||1584||53||23||32||16||7.2|
Table 1: Experiment result of cells cycle on various components
|Stages of Mitosis||Number of times in Eyepiece||Size of cell in each stage|
|Metaphase||1||1X0.001 = 0.001|
|Anaphase||1||1X0.001 = 0.001|
|Telophase||2||2X0.001 = 0.002|
Table 2: Size of cell in each stage of the cell cycle (x 100 magnification)
The present experience demonstrates change in DNA at every stage of cell cycle. Based on the observation of the five datasets, it is evident in prophase cell cycle chromatin start to gather together and the form chromosomes. The nuclear size of chromosome and density is noticed and later disperse. It therefore, means interphase has go nuclear membrane but in the prophase the nuclear membrane is broken. A closer observation of the interphase and prophase from the test conducted reflect the fact that in interphase the cells mitosis several times. The experiment indicates that at metaphase the chromosomes have collected at the center of the cell. It is means the chromosomes are being prepared to move to the oppose side of the pole. This is why at metaphase there is a chromosome at the center of the cell and closer look at t figure 3 of the metaphase will confirm.
However, the five datasets are compared using the Fisher’s exacts test to confirm whether the propose value is different among the values obtained from the experience. In this case, the fisher’s exact test is supposed to test the hypothesis that the duration at each cell cycle depends with the content of the cell. It also supposed to confirm if the hypothesis is true that the cells which are divided mitotically are larger than normal cells, and check whether the higher the percentage of cells which are divided in one phase, the larger duration the cell takes on every phase. But the p-value is used to evaluate how best the data supports the hypothesis. It is used to compare the data collect and the accuracy of the data which therefore, confirm the result obtained from the experience. According to Larsen (2012, p.12), p-value is a probability which restrict certain principles in observation data and therefore, in this experience the p-value is (0.05) which was used to conduct the test.
The experiment indicates that the size of the cell changes as the cycle continues. However, Table 2 indicates the size of cells in every phase. The result shows that the size of cells in very stage increases from interphase to telophase (Gogoi, Saurav, Sayak, & Mohammad, 2016, p. 32). It means the sizes of the cells which are undergoing interphase are usually tinny compare to size of cells at other stages which is approximately 0.001. It is because chromosomes when in the cells are always uncoiled and not divided as well. And since and the cell size of the chromosomes cannot be verified because at prophase there is not prophase cell.
The data collected is different with control data because the experiment discovered that the cell cycle time depends on the size of the cell and the content as well. It is discovered it is similar with control data because the number of cells at every dataset are different and the way it is reflected on the result from the experience. (Gogoi, Saurav, Sayak, & Mohammad, 2016, p. 21).
Based on the result obtained it is evident the three fertilizers catalyze the reaction and therefore, increase the mitosis of the cells. It is discovered that the manure treated root has a mitotic index of 5.8, which is the lowest while the organophosphate treated roots has mitotic index of 7.9, the highest among the three fertilizer and Babybio has mitotic index of 7.2. This means that manure treated root is not a fertilizer and therefore, it does not have organic element. The Organophosphates is the best fertilizer since it has the highest mitotic index and the highest number of cells at the interphase. The manure Treated roots are not working despite the fact that it had the highest number of cells, it still register the lowest mitotic index and from the experience it is clear the onion roots do not react quickly to manure compared to organophosphate and Babybio treated roots.
Antonin, W., & Heinz, N. 2016. Chromosome condensation and decondensation during
mitosis. https://www.sciencedirect.com/science/article/pii/S0955067416300059 , 2-45.
Buttitta, L., Yiqin, M., & Kiriaki, K. 2015. How the cell cycle impacts chromatin architecture
and influences cell fate. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4315090/ , 2-35.
Gogoi, P., Saurav, D., Sayak, D., & Mohammad, Z. A. 2016. Effect of Organophosphorus
Insecticide, Malathion on the Division of Meristems of Allium cepa L. International Journal and Pure Applied , 2-34.
Larsen, M. V. 2012. Cell Cycle and Cell Division: CBS, DTU Systems Biology.
http://www.cbs.dtu.dk/courses/27008/F13/slides/Ch11_presentation.pdf , 1-34.
Appendix 1 Experiment result