Lab report museum: Report 4: Mitosis


onion root tip mitosis lab report

This lab was an experiment designed to analyze how many cells could be observed in each part of mitosis for different areas of an onion root. First, with a prepared slide, area X and Y were located and each counted and recorded of what stages were observed. Then, another onion root tip was prepared and area Z was located. Sep 15,  · Mitotic division consists of two, meiosis and mitosis. The onion root tips occurs the mitosis process. In mitosis process there are 5 stages, Interphase, Prophase, Metaphase, Anaphase and Telophase. Why do we observe the root tips of the onions? This is . In this lab you will be observing plant cells (onion) in the various stages of mitosis, and make time calculations based on the data you collect. MATERIALS: Microscope Prepared slides of a longitudinal section of Allium (onion) root tip. You can obtain these from any science supply company.

Observing Mitosis | Mitosis | Cell Cycle

OBJECTIVE To prepare some slides of actively dividing plant tissue To observe the stages of the cell cycle in living tissue To consider the duration of the stages of mitosis in relation to the whole cell cycle To develop certain experimental skills, namely working safely, the use of microscopes, producing valid results and recording results.

These cell divides either mitotically or meioticallywhich is based on its location. Mitotic cell division take place in somatic cells which means all the cells in the body except the germ cells as they divide through another process called meiosis.

Basically, mitosis is the process where an eukaryotic cell separates the chromosome in its cell nucleus into two identical sets in two separate nuclei which is known as two identical daughter cells. Mitosis doubles the number of cells without changing the genetic content.

Mitosis which is known as M phase occurs after interphase which has three stages namely G1 phaseS phase and G2 phase. M phase is generally followed by cytokinesis which bring means of dividing the cytoplasm into two cells containing roughly equal shares the cellular components. Mitotic phase onion root tip mitosis lab report M phase generally have four stages namely prophase, metaphase, anaphase and telophase.

Some of stages can be even divided as early phase and late phase. Cytokinesis generally come together at the end of telophase stage. Cytokinesis in plant cell occur as the cell plate forms, thus dividing the daughter cell. Cell cycle is control by control chemical cyclins. These cyclin build up and attach to enzymes forming cyclin-dependent kinases CDKswhich means they add phosphate group to phosphorylates, changing shape and bring next stage of cell cycle, onion root tip mitosis lab report.

Mitosis is significant as they provide cell replacement, regeneration, and involve in onion root tip mitosis lab report reproduction. During Prophase. Figure 13 : Onion cell tip 1 Onion roots are used to view mitosis as the roots are easy to grow in large number, the cells at the root tip are actively dividing resulting in many cells that will be in mitosis stage, the tips can be squashed during preparation on microscopes slide so that individual chromosome can be observed and the presence of choromosomes that can be stained to make them more easily observable.

There are three cellular regions near root tip of an onion. The root cap contains cells that cover and protect the underlying growth region as the root pushed through the soil.

Second region of cell division known as meristem is where cells are actively dividing but not increasing significantly in size. And onion root tip mitosis lab report third region is cell elongation, where the cell are increasing in size, but not dividing. Since each cell has only eight chromosomes so it is relatively easy to see them once they condensed.

In order to see the chromosome inside the cells, the cells must be separated and spread out into a layer that is ideally just one cell thick. Plant cells such as onion cells are glued together by a middle lamella of pectins. Hydrochloric acid will break down the pectins that hold the cell together. TB is quite useful to stain fixed tissue but it only provides minimal information about the chemical make up of a tissue or onion root tip mitosis lab report. It has a strong affinity for the granules in mast cells, one of the wandering cells of connective tissues and also often requested as a specific stain for mast cell tumours.

In this experiment, toluidine blue was used to stain the cells to make the chromosomes being shown up so they will be easier to be observed under the microscope later. The higher the percentage of dividing cells in one phase, the longer in time the cells spend on the phase the phases. Two watchglasses labeled HCl and Carnoy were prepared.

It was then left for 4 minutes time taken using stopwatch. The root tip then transfer using forceps into Carnoy watchglass for another 4 minutes time taken using stopwatch 5. The root tip was then taken out using a pair of forceps and was placed on a glass slide.

The root tip was then stained with a few drops off toluidine blue or carbol fuschin for 2 minutes time taken using stopwatch. The excess stain surrounding the root tip was blotted way or soaked up gently and carefully using tissue paper. One or two drops of distilled water was dropped on the root tip when the stain has been blotted away. A cover slip was lowered gently to cover the root tip so that no bubble is trapped inside the cover slip.

Lateral movement of the coverslip was avoided The cover slip was then pressed firmly using thumb carefully with putting paper towel on it to spread the root tip into a single layer cells making the cells more easily and clearly viewable. The preparation slide was observed under the microscope X magnification. The cells that undergoing different stages of mitosis was searched and identified.

The following were counted : i. The total number of cells in microscopic field The total number of cells containing visible chromosome. The size of cells that undergoing each stages of mitosis was calculated by comparing the scalee on the eyepiece graticule with the micrometer slide. Tables were drawn to summarise the results. Size of cell in each stage m 14 x 0. The stain is blotted and the tip is covered with few drops of water. It is then covered with coverslip and pressed gently using thumb forming single layer of cell.

From low power to high power of a microscope, the cell is observed and the mitotic rate is recorded. The preparation of onion root tip freezes the mitosis process at one point, thus, the higher the percentage of the cell in one stagethe higher the time spent on that onion root tip mitosis lab report. Based on table one, interphase recorded the highest number of cell followed by anaphase, metaphase and telophase.

Cytokinesis is not identified as it is not a mitosis part, but incidence that hppen after mitotic phase. This shows that the time spent on interphase is the longest. Basically, when a group of cell is dividing rapidly, high proportion of the cell undergoes mitosis while nondividing group of cell stays in interphase stage of the cell cycle. Mitotic index is used to calculate amount of cell division occurring in a tissue. Figure 14 in my result section shows the image of onion root tip cell under microscope x magnification.

In this field of view, as stated in table 33 cells can be viewed have visible chromosomes out of 17 cells. The non-visible chromosome cell either can onion root tip mitosis lab report in interphase or cytokinesis.

From these observation, mitotic index can be calculated giving result of 0. The number of cells which undergo different stages of mitosis and their corresponding percentages are tabulated in Table 1. The table shows that the interphase stage has the highest number of cell in the field view which onion root tip mitosis lab report 95 cells and thus gives This is followed by prophase stage which gives 17 cells thus record Then both metaphase and telophase stage have 1 counted cells and thus make up 1.

These data can be illustrated in pie chart as in the Pie Chart 1. Stage of mitosis corresponding to their percentage of cells is shown in another formpie chart. The Pie Chart 1 shows that the interphase has taken the largest portions. Hence, it shows that cells spend the longest time in interphase during the cell cycle compared to the other phases in mitosis.

During interphase, the cell undergo three subphases namely G1 phase. S phase and G2 phase. During all three subphases, the cells growth by producing proteins and cytoplasmic organelles. Hence, it is clear that interphase spend the longest period of time in the cell cycle as the cells increase in mass and size, replicate their DNA and carry out normal activities.

Meanwhile, among the other four phases in the M phase, onion root tip mitosis lab report, the prophase is the longest periods spend by the cells followed by anaphase.

Metaphase and telophase are the least timeconsuming by the cells. This is because, during the prophase, onion root tip mitosis lab report, the chromosomes coil and condensethe centrioles begin to separate and start to form the mitotic spindle. Hence, these processes take a longer time compared to the other stages in the mitotic M phase. Table 3 shows sizes of cell in each different cell stage.

The sizes of the cells are increasing from the interphase to the telophase. The sizes of the cells that are undergoing interphase are the smallest compare to the other stages which is This is because during this stage, the chromosomes in the cells are uncoiled and are not divided.

Since there is no prophase stage cell in viewed field, thus the size of the cell is cannot be justified. But, the overall study suggest that the prophase stage has the second largest size of cell and followed by metaphaseanaphase and telophase.

The activities that happen inside of the cells during different stages results in the size of the onion root tip cell. The sizes of the cells are calculated by comparing the scale on the eyepiece graticule and the scale on the micrometer slide. Beside using toluidine blue stain, orcein ethanoic stain can also be used as the other choice of stain to conduct the experiment. In some preparation, only few dividing cell is observed. This is because maybe a wrong section is cut from the root which is not the root tip onion root tip mitosis lab report actively dividing apical meristem of the root is not being viewed.

There is also the possibility that the root used no longer have dividing cell due to X- ray or heavy metal emanation. As stated earlier in the introduction, cellulose walls of the plant cells are held together by cement called middle lamella. Treatment with hydrochloric acid breaks this wall and this is essential as it allows cells to separate and produce one cell thick preparation, making viewing of individual cells possible.

The result is reliable if repeated measurement which almost have similar values. Besides, onion root tip mitosis lab report, the length of the cell is measured three times to obtain a mean value. Next, the eyepiece graticule is used with full care and it has been correctly calibrated using stage micrometer and under supervision of lecturer. Onion root tips are very fragile onion root tip mitosis lab report easily damage. The presence of xylem in the onion root tip makes the maceration more difficult.

Thus, to prevent misleading results, the end of root tips were not cut. The onion root tips should be handle with extra care. Cutting the wrong end of onion root tip will give arise to inaccurate results, onion root tip mitosis lab report, thus it was not carried out.

Since the prepared specimen are very thin one cell layer thickit enable us to be clearly observed under the microscope.

But extra care have to be taken as the cover slip is pressed. It should be pressed gently co that the pressure will spread the cells into single layer.


Mitosis - Google Документи


onion root tip mitosis lab report


Stages of Mitosis Lab Report - Free download as Word Doc .doc /.docx), PDF File .pdf), Text File .txt) or read online for free. mitosis4/5(4). In this lab you will be observing plant cells (onion) in the various stages of mitosis, and make time calculations based on the data you collect. MATERIALS: Microscope Prepared slides of a longitudinal section of Allium (onion) root tip. You can obtain these from any science supply company. report on observing mitosis (Autosaved) Lab Report Chemist Chapter 7. the cell is observed and the mitotic rate is recorded. The preparation of onion root tip freezes the mitosis process at one point, thus, the higher the percentage of the cell in one stage, the higher the time spent on that stage. Mitosis Onion Root Tip Lab. Uploaded 5/5(17).