Observing Mitosis In The Cells Of Garlic Biology Essay

Observing Mitosis In The Cells Of Garlic Biology EssayAim To cite the introduces of the cell cycle in living tissue, generally and specifically in the meristematic cells of the result of garlic and hence consider the duration of the stages of mitosis in relation to the alone cell cycle.IntroductionThecell cycle, orcell-division cycle, is the series of events that takes place in acellleading to its division and duplication (replication). In cells with extinct a lens nucleus (prokaryotes), the cell cycle occurs via a process termedbinary fission. In cells with a nucleus (eukaryotes), the cell cycle provide be divided in devil brief periodsinter variant-during which the cell grows, accumulating nutrients needed for mitosis andduplicating its DNA-and themitosis(M) phase, during which the cell splits itself into ii distinct cells, often called daughter cells. The cell-division cycle is a vital process by which a one-celledfertilized eggdevelops into a mature organism, as well as the process by whichhair,skin,blood cells, and some internal organs atomic number 18 renewed. 1Figure 1 The cell cyclehttp//adasilva.glogster.com/chapter-10-bio/Mitosis is the process that facilitates the equal partitioning of replicated chromosomes into two identical groups. in the beginning partitioning can occur, the chromosomes must give-up the ghost aligned so that the judicial separation process can occur in an orderly fashion. The alignment of replicated chromosomes and their separation into two groups is a process that can be observed in close to all eukaryotic cells. 2Both the alignment and separation processes are the consequence of the chromosomes interacting with filamentous proteinaceous structures, known as microtubules. The microtubules get organized into a biconical set known as a arbor, which forms early in mitosis, and then disassembles as mitosis nears completion. Mitotic spindles are manifest in living cells with the polarizing light microscope. Some o f the spindle microtubules become attached to the chromosomes at sites known as kinetochores. The kinetochores cannot be seen with the light microscope, but they reside near the place on the chromosome known as its centromere, which can be observed with the light microscope. There are two kinetochores on several(prenominal)ly replicated chromosome (one on individually chromatid), and when the replicated chromosome splits apart at its centromere at the onset of anaphase, each daughter chromosome possesses one centromere and one kinetochore. The linkages between kinetochores and microtubules are thought to be primordial in controlling both the positioning of the replicated chromosome at the central portion of the spindle during the alignment phase, and in moving the daughter chromosomes apart after they split at their centromeres. The separation of daughter cells from each other is a process known as cytokinesis, and is separate from mitosis. In cytokinesis, animal and ingraft cel ls differ considerably from each other. These differences are the consequence of having or not having a cell wall. Cytokinesis in fungi reveals some similarities with plant cells, and exhibits other features unique to the group.2Figure 1 Illustration of the process by which somatic cells mul speckly and divide.http//www.accessexcellence.org/RC/VL/GG/mitosis.phpThe warning utilise in this investigate is the parentage of garlic where the meristematic cells are actively dividing. Cell division in flowering plants takes place in particular regions of the plant calledmeristems. Cells in meristems are not specialized for any particular function and divide repeatedly by mitosis. Some of the daughter cells remain meristematic others cease dividing and become differentiated into appropriate cell types depending on their position. The root tip meristem is usually a denser white and more round than the cut end. Chromosomes in root tip tissue are made visible with the stain. Dividing cells (if present) will show up understandably with chromosomes in different forms according to the stage of mitosis. Individual chromosomes (as tightly-coiled threads) are visible during anaphase. The links between the cellulose walls of plant cells are broken down by the treatment with hydrochloric acid. This ensures that the stain can penetrate the cells and allows the tissue to be squashed out one cell thick. 3References1 http//en.wikipedia.org/wiki/Cell_cycle2 http//www.life.umd.edu/CBMG/faculty/wolniak/wolniakmitosis.html3 http//www.practicalbiology.org/areas/advanced/cells-to-systems/cell-division/investigating-mitosis-in-allium-root-tip-squash,121,EXP.htmlObjective Mitosis occurs in four phases as a continuous process without break in between the phases. Before mitosis, the cells are in tranquillity during interphase stage. The activity of chromosomes is significant in determining the stages of cell division. Therefore, to observe the chromosomes, the root cells are stained. Ther e are two types of stains officed the toluidine blue stain. The toluidine blue stain causes the cytoplasm to appear light blue in colour while the chromosomes appear dark blue. In this experiment, the cells in the root tip of garlic is squashed, stained and observed under compound microscope to observe the stages mitosis.Apparatus Compound microscope, 2 Watch glasses, dropper, tissue paper, microscope slide, cover slip, forceps, mounted needles, stop anticipate, scalpel or sharp knife, eye protection, small sample tube, filter paper, eye goggles.Materials Toluidine blue stain, 1M hydrochloric acid, 1 clove of garlic with roots, cold distilled waterProcedure1-2 cm of root tips of growing garlic roots are cut off. The root tips are ensured to be chosen from those which are white and have a firm rounded end.The root tips are put into watch glass containing 2 cm3 of 1 M hydrochloric acid for exactly 5 minutes.The root tips are then transferred into watch glass containing approximately 5 cm3 cold water, and left for 4-5 minutes. The root tips are then dried on filter papers.Figure 3 The root tips are transferred into glass with cold waterThe root tips are then transferred onto a clean microscope slide. 4-5 mm of the root tips are cut and kept, while the rest are discarded.The root tips are gently broken up with a mounted needle by a process called maceration.Figure 4 The root tips are break upA small drop of toluidine blue stain is added to the root tips and left for 2 minutes.The tips are covered with a coverslip, and blotted firmly with several layers of tissue. The coverslip is pressed gently to spread the root tip.The samples are then viewed under the microscope (x40 magnifications) and the nuclei of the cells are located.The microscope lens is switched to higher power (x100, x400 and x1000 magnifications and look for cells with chromosomes.Figure 5 The cells are observed under light microscopeThe regularly shaped, actively dividing cells are focused and co unted for every phases of mitosis.The data obtained are recorded and tabulated.ResultsStages Of MitosisInterphaseProphaseMetaphaseAnaphaseTelophaseTotalCell counted221533235Percentage62.914.38.68.65.7100Table 1 The stages of mitosis and the respective cell count and percentageCalculation of the mitotic king Mitotic index = number of cell containing visible chromosometotal number of cells in the field of viewMitotic index =InterphaseInterphase is the period where the cell prepares itself before cell division. It is a phase before the mitosis. The chromosomes are uncoiled and it fills the nucleus. DNA replication occurs during this stage. The nuclear envelope is visible the centrioles appear and so do the nucleolus.ProphaseDuring prophase, the replicated chromosomes undergo extensive condensation or coiling. The chromosomes are greatly thickened and shortened but are still contained within the nuclear envelope. Prophase ends with the sudden dispersion of the nuclear envelope. The ch romosomes start to coil, shorten, and become distinct. The mitotic spindle or polar fibers begin to form from the poles of the cell towards the equator.MetaphaseChromosomes line up along the equator of the cell or what is called the metaphase scale leaf. Polar fibers have reached the centromeres of the chromosomes and have begun interacting with them. Each kinetochore, plate like structure of the replicated chromosome is pointed toward one side of the spindle. The replicated chromosomes converge toward the center of the spindle, and once they get there, significant movements cease. On either sides of each centromere are sites for kinetochore microtubule.AnaphaseAnaphase commences with the initial splitting of sister chromatids at their centromeres. These daughter chromosomes then begin to separate from each other, each moving away from the metaphase plate and toward one of the two spindle pole regions. Anaphase ends when the daughter chromosomes reach the end of the cell. Since the sister chromatids are identical copies of the original chromosomes, each pole of the cell will have a set of complete and identical chromosomes as in the parent cell.TelophaseIn telophase, the daughter chromosomes arrive at the spindle poles and are eventually redistributed into chromatin. afterward complete separation of the chromosomes and their extrusion to the spindle poles, the nuclear membrane begins to reform around each group of chromosomes at the opposite ends of the cell. The nucleoli also reappear in what will eventually become the two new cell nuclei. A new nuclear membrane forms. The new cell walls grow to form the two new, identical daughter cells. The cytokinesis process starts to happen in order to complete the division of the two new cells.DiscussionAfter observing the mitosis process, we knew that percentages of the cells in each stage are different. In the experiment using toluidine blue stain, we observed that 22 cells out of 35 cells undergone interphase which covered 62.9% of the cells. There are 15 cells undergone prophase diligence 14.3% of the cells. Metaphase and anaphase have the same percentage which is 8.6%. While 2 cells undergone telophase which covered 5.7%. The mitotic index using toluldine blue stain is which suggest that only 37.14% of the cells in our view were undergoing mitosis and the rest are still in interphase. The percentage of cells in each stage is related to the length of epoch a cell spends in each stage of mitosis. The greater the percentage of cells in a stage, the longer the time spent by each cell in that stage.Based on the table 1, it is clear shown that the largest percentage of cells is found to be at interphase. Interphase is often referred as the resting phase. Interphase is the stage in which the cells prepare themselves to undergo mitosis. Since interphase has the largest percentage of cells, therefore each cell spends the daylong time macrocosm at interphase stage. Metaphase and anaphase occupie s the same length of time and same percentage of cells. This means cells spend almost equal length of time being at both phases. Telophase on the other hand, has the lowest percentage which means the shortest period of time a cell spends is during telophase. Prophase, being the first stage of mitosis has the second base highest percentage of cells. It means compared to metaphase, anaphase and telophase, prophase is the stage of mitosis in which each cell spends the most time. From the results, we knew that most of the cells spent longer time in interphase because cell growth, replication of the chromosomes, and umpteen other activities are taking place during this time. The cells need to prepare first for the mitotic division to occur. On the other hand, based on results on table 2, is it clearly shown that, the sizing of cell during interphase is the smallest among all followed by the size of cell during prophase, metaphase, anaphase and finally the size of cell is the biggest du ring telophase. This is because, during interphase the cell will never grow in size exactly as the cell prepares itself for cell division. Meanwhile, during telophase the cell actually splitting into two daughter cells and it is obvious that the cell would have grown in size.This experiment use the garlic root tips tissue for observing the mitosis process because the stages of development in plant growth can be distinctly observed at this part which is known as meristem. This meristem is actively divided by mitosis. So, every stage of mitosis can be observed clearly. We ensure that our results are reliable because we use 3 samples of root tip. This could minimize the error during this experiment and we can compare the results for each sample. Besides that, we stained the samples using toluidine blue first so that we can observe the chromosomes clearly. We believed that our results are valid because the outcomes from the experiment are the same with what we expect based on the theory and our results are quite similar with the other groups results. non only that, the usage of toluidine blue is reliable, cheaper and easy to handle with. In a way, it is simple and it helps produce results quicker compared to the usage of other staining.ConclusionMitosis can be divided into four different stages prophase, metaphase, anaphase and telophase. In conclusion, the mitosis process is a random process. So, different types of sample will have different length of time for mitosis to complete. different than that, the longest stage of cell cycle is interphase with the highest percentage followed by metaphase and anaphase while the shortest stage is telophase with the lowest percentage. The greater the percentage of cells in a stage, the longer the time spent by each cell in that stage. Hypothesis is accepted.