Materials This lab requires prepared slides of whitefish blastula, onion root tips, and Sordaria, pencil, paper, a light microscope, and a chromosome simulation kit. Next the cell begins metaphase, where the spindle attaches to the centromere of each chromosome and moves them to the same level in the middle of the cell. However, learning to use a microscope properly is an important skill for science students to have. There are two parts to the procedure of the experiment whereby the first is staining and observing mitosis in onion root tips and the second being observing and comparing…. Finally, it is predicted that the cells will not look large or clear, but it will still be able to give me a general idea of what is going on. This is where crossing over occurs resulting in the recombination of genes.
Mitosis is a process by which a cell divides to form two daughter cells. Just before mitosis the cell is in interphase. When a cell begins to divide, the chromosomes are duplicated. Instead, the cells would have been growing during interphase. Figure 2: The duration of the stages of mitosis can be determined by counting the number of cells in mitosis at a given time and multiplying that value by the average duration of mitosis in an onion, which is approximately twenty-four hours.
Telophase I then prepares the cell for its second division. Stage Observed occurrence in representative microscope fields Duration number of cells % of total cells minutes % of total time Prophase 216 85. A final experiment is to use different varieties of plant and animal cells with different rates of growth in order to determine how long it takes their cells to complete the cell cycle. In this slide, a majority of cells are in interphase, and a notable telophase is seen in the center. Put in a small volume of ethanoic acid on a watchglass or other shallow dish for 10 minutes. Meiosis occurs in the primary sex cells leading to the formation of viable egg and sperm cells.
It can help to break the hydrogen bonds contain in it. Results Whitefish Blastula Number of Cells Field 1 Field 2 Field 3 Total Interphase 42 36 47 125 61. Dividing cells have a regular pattern of events,… 919 Words 4 Pages happen by either mitosis or meiosis, depending on what type of cell is invovled. At first glance Mitosis seemed not so complicated until realising the intricacies of the process. It should be taken into care that pressing of stained specimen should be strong to make image more clear and transparent.
Lesson organisation The allium roots need to be prepared 1-10 days in advance of the lesson. I grasped the basic principle of mitosis in its simplest form, cells divide. In a certain cell, the chromosomes condensed chromatin , that were lined up in the previous stage, break apart from their duplicates and head towards opposite centrioles. If your observations had not been restricted to the area of the root tip that is actively dividing, how would your results differ? Mitosis is the scientific… 1029 Words 5 Pages Discovering Mitosis its not just a phase you going through Mitosis tried its best to break me. Sordaria form a set of eight ascospores called an ascus. As this experiment involved observing cells, possible sources of error include the misidentification of cells.
Julie the diagram on the right is not related to the sample count we did in the table. Part Two: Determining the Rate of Mitosis in Plant and Animal Cells. The first signs of the spindle begin to appear. In this lab, you will determine the relative length of time each phase of mitosis takes in the meristem of an onion root tip on a prepared slide. This ensures that the stain can penetrate the cells and allows the tissue to be squashed out one cell thick.
Propionic orcein made with propionic acid rather than ethanoic has the advantage that it evaporates more slowly, and is sometimes suggested for this practical. I multiplied the percent of the total number of each cell in a phase by 1440, the number of minutes in a day, which is the time an onion cell takes to undergo mitosis. Leave overnight, then filter and store in a tightly-stoppered dark bottle. Why is the whitefish used to study mitosis? This product is approximately equal to the time a cell spends in each stage of mitosis. Toluidine blue — Hazcard 32 describes this as low hazard. Hypothesis It can be predicted that all somatic cells will undergo all the stages of mitosis multiple times in their lifetime, that the viewed will be able to see the chromosomes at one stage of mitosis.
I found it difficult to distinguish cells in anaphase from cells in telophase, which may have affected my results. Interphase and the stages of mitosis are seen in Figure 1 below. Explain why whitefish blastula and onion root tips are selected for a study of mitosis. They can also be prepared by the teacher or students on blank slides with coverslips. This process allows increased genetic variation due to crossing over where genes can be exchanged. Teaching notes Cell division in flowering plants takes place in particular regions of the plant called meristems.
The only change is the number of chromosomes. What about it makes it easy to identify? Metaphase can be seen as chromosomes that have lined up along the center of the cell. Sketch one cell in any stage of mitosis. That cell had X number of chromosomes. Interphase takes up about 81% , with Prophase at 12. Next, anaphase was simulated as the homologous pairs were separated and then telophase was simulated by pushing the chromosomes into two separate cells circles. Graph 2 As seen in Graph 2, this pie chart represents the total number of minutes per cycle a cell spends in each stage.
Materials and Procedure Materials List —1 Light Microscope, outfitted with a 10X eyepiece and 4X, 10X, and 40X objective lens —Prepared Microscope Slide of 3 Onion Root Tips —Prepared Microscope Slide of Whitefish Blastula Procedure Part One: Observing Mitosis in Plant and Animal Cells 1. Interphase — 81% Prophase — 12. I identified and classified the cells based on their stage in mitosis: interphase, prophase, prometaphase, metaphase, anaphase, and telophase, as depicted below in Figure 3 and Figure 4 Figure 3: Figure 4: 4. To define the number of cells visible at point of view image which enable objective to see during reviewing without changing the position of microscope it was calculated the quarter of circle row by row cause cells are not same, so rows are not same. Remember, that mitosis occurs only in areas of growth, so finding a good spot to study it can be challenging. Anaphase begins when the chromatids are separated and pulled to opposite poles.