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The phase of mitosis within the cell cycle
The cell cycle is the division of a predecessor cell that passes through a series of stages where it grows, doubles its size and, finally, is divided to give two daughter cells that will begin again the cycle. The phase of myitosis consists of the cell cycle and in it there are several phases that are the profase where the DNA begins to condense, then the metaphase comes where the two chromatids United SistersMititic spindle, anaphase begins with the breakage of connections between sister chromatids at the centromere. The appropriate material for your observation is the meristematic tissue of the roots of the onion.
According to Carola d., (1995) mentions that the cell cycle is the universal mechanism for reproduction of eukaryot cells whose main event is the reproduction and duplication of the number of chromosomes, the myitosis being the division mechanism of the chromosomes, the nucleus and the entire cell. During the mitosis, the destruction of the nuclear membrane and the formation of the acromatic spindle that guarantees the equitable distribution of the chromosomes (chromatides) spiralized and previously duplicated between the dormants between the dormant chromosomes are observed. The growing organism cycle comprises 2 stages: the interface, frequently prolonged, and the mitosis, shorter;consisting of 4 phases (Profase, Metaphase, Anaphase and Telophase. During the interface it is possible to observe “S” of synthesis, in which the replication of the chromosomes occurs, as well as 2 periods “G”, G1 previous of the period, and G2 after him (pp 14).
In the mythosis phase there is a division in stages: Profase begins with DNA condensation, so that chromatids become visible in isolation, and with the disappearance of the nucleolus. In the metaphase the two United Sisters chromatids form the chromosomes, which are displaced towards the center of the mititic spindle, equidistant to the two centers, forming the so -called equatorial plate. Anaphase begins with the breakage of connections between sister chromatids at the centromere level, each chromatid Ira towards one of the centers. During the telophase the nuclear wrapped around each chromatid set is organized again and cytocinesis that supposes the separation of the cytoplasm of the stem cell into two parts that will shape the daughter cells (megías et al., 2017 pp 10-12).
According to González (2003, pp. 135), myitosis is a process of division of the cell nucleus, which ensures an equitable distribution of the genetic material between daughter cells. During the stages of mitosis, DNA is compact, forms chromosomes, organize and secrete, and finally are discouraged to form the nuclei of daughter cells (Megías et al., 2017, pp. 4). The appropriate material for your observation is the meristematic tissue of the roots of the onion (González, 2003, pp. 135).
The use of hydrochloric acid is for the degradation of the cell wall and be able to observe the cells. Carnoy’s solution is a fixing solution that helps soften carmine tissues and acetate is to dye cells and be able to observe the different mitotic phases (Doria et, al., 2016).
Observe the different phases of the mitotic division process in onion roots (Allium Cepa), in growth.
- Know the mythosis plates preparation procedure.
- Microscopically observe the phases of mitosis.
- Identify the phases of mitosis.
Materials and methods
- Porta objects
- Cover objects
- Paper towel
- 96% alcohol
- Masking tape
- Mask, gloves, apron.
- Onion root
- Carnoy solution (60ml of ethanol+30ml of chloroform+10 a. acetic/100ml)
- 10% hydrochloric acid
- Carmín Aceto (acetic acid (45%) + carmine red (dye))
- Five to eight days before the practice the onion is prepared. First, a scraping with a blade is made by eliminating the dry or dead roots that are at the base of the bulb. In a bottle with water place the onion (annex. Fig. 1). Keep the base of the wet onion and change the water of the container every 24h.
- When the roots reach 3 cm long, remove the onion from the bottle and execute a root cut at the last centimeter of the tip.
- Place the roots in the Petri box with carnoy fixing solution for 20 minutes.
- After 20 min place them in 10% hydrochloric acid for 10 minutes (annex. Fig. two).
- Proceed to rinse the roots (annex. Fig. 3).
- Place the washed roots in a container with Aceto Carmín, for 20 minutes (annex. Fig. 4).
- Proceed to get the root from the carmine aceto and locate it on a slide.
- Use a cover to place it on the slide, and make a slight pressure with your finger to get an extension of the preparation.
- Once sealing he covers objects, leading to the microscope and observing the different phases of mitosis.
In the profase, the chromatin is in the form of a thread and then condenses to form the chromosomes.
In the metaphase, the sister chromatids that form the chromosomes, are aligned in the equatorial plane of the cell. The mitotic spindle is formed.
In anaphase, sisters chromatids separate and considered them as independent chromosome. Each chromosome begins to migrate to the mitotic spindle poles.
In telophase, independent chromosomes are grouped into the opposite poles of mitotic spindle, nuclear envelope begins to form. Finally cytokinesis occurs and two daughter cells are formed.
A similar experiment by López et al., 2008 mentions that the different phases of cell division or mitosis were described with the light microscope since the nineteenth and today are recognized in all texts of cell and molecular biology. Therefore, the different phases of mitosis can be recognized with relative ease according to morphological parameters such as chromatin condensation and chromosomes, as well as the integrity of cell nuclei or the formation of division grooves (pp 88).
Onion roots are used for this waiting, since the tissue of its roots is meristematic and is in constant division, that is where the process of myitosis can be observed.
- The process for the observation of myitosis was first with the cutting roots of onion which went through different solutions (hydrochloric acid, carnoy solution and carmine acetate), which provided the cell the tissue softening and staining forTo be able to observe the phases of mitosis on the plates sampled with onion roots.
- The process of mitosis was observed in different plates sampled with onion root: Profase, metaphase, anaphase and telophase reaching the total division of the stem cell into two daughter cells, which again will enter the same cell division cycle.
- Each of the phases were identified with the microscope and took photographs of these phases.
- Carola Escobar, D. T. (nineteen ninety five). The cell cycle in vegetables. Your study, importance and applications. Lima Peru.
- Doria, j., Peralta, a., & Paternina, J. (2016). Mitosis in the Practical Onion Raiz #13. Córdoba, Spain.
- González, p. (2003). Laboratory and classroom practices . Madrid: Narcea, S.A.
- López, r., Safe, m., Crúz, s., Zabala, g., & Jiménez, L. (2008). Visualization of mitosis with the atomic force microscope. Mexico.
- Megías, m., Molist, p., & Pombal, M. (2017). Plant Histology Atlas. The cell. Cellular cycle. Pontevedra, Spain.eleven. Annexes