Experiment Mitosis - Essay Example

? Experiment mitosis 31 October 31, Experiment mitosis Cell division is a fundamental process in both plants andanimals’ growth and development as well as recreation. This paper investigates the mitosis process in both plants and animals’ cells to identify distinct stages of mitosis and the structure of cells at each stage. The experiment identifies similarity in mitotic stages for cells in both plants and animals. The mitotic process leads to division of one parent cell to form two identical daughter cells that can further undergo subsequent mitotic divisions. Introduction Cells are the fundamental elements of living things, both plants and animals. Consequently, realized mechanisms originate from cells and manifest in organs and the entire organism. Mitosis and meiosis are some of the fundamental processes that take place at the cell level. They refer to cell divisions that lead to generation of new cells to replace dead or worn out cells, generation of cells for development of organs, and cell division towards growth. Mitosis leads to generation of identical daughter cells for growth or replacement of cells in organs. It takes place in a number of stages, interphase, prophase, metaphase, anaphase, telophase, and cytokinesis (Goldberg and Goldberg, p. 77- 80). The interphase is a preliminary stage in cell division that precedes the mitotic stages. It is fundamental as it forms the largest percentage of a cell’s life. The major activity at this stage is replication of cell proteins within cells and developments to visibility of cell nucleoli. Mitosis however has four stages that result into cell division. The first stage is the prophase, followed by metaphase, anaphase, and telophase respectively (Goldberg and Goldberg, p. 79). At the prophase, “strands of chromosomes begin to condense” and can be seen with the aid of a powered microscope. Visibility of the nucleoli however disappears while fibers develop in the cell’s cytoplasm. The developed fibers emanates from a pair of centrosomes that stretch to opposite poles of the cytoplasm. Disintegration of the “nuclear membrane begins” at this stage and marks the end of the prophase and the process moves to the metaphase (Goldberg and Goldberg, p. 79). At the metaphase stage, the chromosomes are arranged along a plate that is perpendicular to the centrioles’ plane and the “spindle fibers” interlink the centrosomes and the chromosomes (Goldberg and Goldberg, p. 79). A new phase, the anaphase is then marked by disintegration of chromosomes into centromeres that are then attracted to the centrosomes along the fibers (Goldberg and Goldberg, p. 79). The cell then enters a new phase, the telophase, where the pulled chromosomes converge at the opposite sides of the cell, along the fibers and the nuclear membrane begins to reappear. Each set of chromosomes assumes the normal thread like structure and the nuclear membrane develop around each group of chromosomes to form two nucleuses within the cytoplasm (Toole and Toole, p. 139). The cytokinesis process, where the cytoplasm divides to form two different cells then follows this (Goldberg and Goldberg, p. 79- 80). The structure of the cells in plants and in animals may however be different. This is because of a number of factors such as the lack of significance of the spindle fibers in the plant cells. The nucleus, rather than spindle fibers in plant cells, moves to define the new position of chromosomes in the mitosis process (Cassimeris, Plopper and Lingappa, p. 952). This paper seeks to explore mitosis in plants and animals’ cells. It aims at describing chromosomal events in mitosis, differentiating between plants and animal cytokinesis, and explaining why mitotic divisions are necessary in living systems. Materials and methods The experiment used the following materials and equipments Allium root tip slide Whitefish blastula slide Living onion roots Acetic oxcelin Mitosis models Methods Using a prepared slide of onion root tip and a 4x objective, a section of the root tip was identified and the objective lens adjusted to 10x to focus on the area above the root tip, not the very top. Each of the mitosis phases were then located and the objective adjusted to 40x for studying structures of the chromosomes and other cell structures. Each phase was then observed and drawn. Similarly, using a 4x objective, a whitefish blastula slide was observed. Focus was shifted to 10x objective to identify each of the mitosis phases. The objective was then shifted to 40x to analyze the structure of each phase. Results The following are the observations from the onion slide Interphase Prophase Metaphase Before anaphase Before the anaphase, the dyads are arranged as in the metaphase. After anaphase Telophase (Mitosis, p. 1) Similar orientations were noted for the whitefish mitosis phases. Discussion questions Question 1 When DNA replication takes place DNA replication takes place at the interphase stage, before the mitosis process begins. Necessity of DNA replication The DNA replication is important because it forms the basis for generation of similar daughter cells. This is because the replication process copies the strands that unwind to generate similar chromosomes for each daughter cell. Question 2 Visible and invisible large structures at the prophase The nucleoli are invisible while the spindle fibers are visible. Reason for invisibility The nucleoli are invisible because of disintegration that allows for movements of the chromosomes to their strategic positions for the eventual cell division. Question 3 The major event that occur at the interphase The major event at the intrphase is the DNA replication that prepares the chromosomes for the cell division process. Significance of the event The DNA replication is significant because it forms the basis for development of daughter cells that are similar to the parent cell. Similarity of the formed cells at the end of the tellophase The formed cells bear total similarity to one another as they bear to the parent cell. Difference in the cells The cells bear no difference. Question 5 Number of chromosomes in each daughter cell of an onion cell with 16 chromosomes The daughter cell will have 16 chromosomes, exactly the same number as the parent cell has. Conclusions The results indicate a systematic process that occurs in distinct stages of mitosis. Chromosomes replicate and separate to form a pair of similar chromosomes that consolidate to a new nucleoli of a daughter cell. Mitosis is therefore an important process because it ensures generation of similar cells towards specialized purposes such as growth and replacement of worn out cells. The most important phases are the interphase and the anaphase because the interphase forms the basis of similarity of the daughter cells while the anaphase allows for separation of the pairs of chromosomes towards generation of a pair of daughter cells. Cell structure such as presence of cell wall forms the difference between cytokinesis in plant and animal cells. Works cited Cassimeris, Lynne, Plopper, George, and Lingappa, Vishwanath. Lewin’s cells. Sudbury, MA: Jones & Bartlett Learning, 2011. Print. Goldberg, Debbie, and Goldberg, Deborah. SAT subject test biology E/M. New York, NY: Barron's Educational Series, 2009. Print. Mitosis. Mitosis. JCCC. 2002. Web. 31 October 2012. < http://staff.jccc.net/pdecell/celldivision/mitosis1.html >. Toole, Glen, and Toole, Susan. New understanding biology for advanced level. London, UK: Nelson Thornes. Print. Appendix Structures of the mitosis phases Read More