Staining root tip to observe mitosis
Figure 7 — Elongated cells and nuclei of the root.
Mitosis in onion root tip discussion
They must not have roots, and if there are any cut them away. Get help from an adult. Take a razor blade and cut most of the unstained part of the root. In which phase of mitosis was the number of cells the fewest? Describe how you determined which phase each cell was in. Teaching notes Cell division in flowering plants takes place in particular regions of the plant called meristems. At any rate, garlic and onion are both liliaceae and their mitotic processes are very similar. Stage Observed occurrence in representative microscope fields Duration. At the end, they can no longer be distinguished from the other cells in interphase that surround them. It is recommended that students are familiar with microscopes and how to use them correctly before beginning this experiment, as well as the stages of mitosis and what happens in them. Create a data table with the following headings across the top: Number of Cells, Percentage of all Cells, Time min. Again rinse the root tips with distilled water. They can also be prepared by the teacher or students on blank slides with coverslips.
Create a data table with the following headings across the top: Number of Cells, Percentage of all Cells, Time min. Discard the HCl from the tube using a Pasture pipette to the running tap water.
In the equatorial zone of the cell a new cell wall forms and the two cells separate. Dissection probe with wooden back Microscopic slides and cover slips Water bath Procedure Take the onion plant with newly sprouted roots and cut two root tips using scissors and transfer them into a plastic microfuge tube.
This will be determined by observing the onion root tip under the microscope and counting the number of cells in each phase. This allows the cells to take up the stain and to harden, which reduces the chance of them bursting. Dividing cells if present will show up clearly with chromosomes in different forms according to the stage of mitosis.
Onion root tip mitosis lab results
If you were to give your slide to another lab group to have them repeat your experiment, would you end up with the same cell counts? At the end, they can no longer be distinguished from the other cells in interphase that surround them. The spindle fibres dissolve. You will then use mathematical equations to figure out time spent in each phase for any given cell in an onion root tip meristem. Do not allow the slide to get hot to the touch; you don't want to cook either your fingers or the root. Carefully put the slide on the microscope and focus it under low power 40x is preferred. It is recommended that students are familiar with microscopes and how to use them correctly before beginning this experiment, as well as the stages of mitosis and what happens in them. Leave overnight, then filter and store in a tightly-stoppered dark bottle. Some of the daughter cells remain meristematic; others cease dividing and become differentiated into appropriate cell types depending on their position. If you introduce too many air bubbles, add more stain after squashing, using a fine dropping pipette. Do this for all stages of mitosis. Clean up your lab materials as directed by your teacher and answer the analysis questions. Roots that have been set to sprout for 2 to 5 days seem to give the highest likelihood of finding actively dividing cells. While these types of diagrams are definitely beneficial for visualizing and understanding the stages of mitosis in eukaryotes and connecting them all together to describe the process of mitosis, it is still a good idea to show students how the stages actually look under a microscope in an actively dividing group of cells. Investigation k View the root tips under a microscope x magnification and look for the chromosomes within cells which are actively dividing.
Background and Purpose Mitosis is constantly happening the meristems or growth regions of roots in plants. This ensures that the stain can penetrate the cells and allows the tissue to be squashed out one cell thick.
You will then use mathematical equations to figure out time spent in each phase for any given cell in an onion root tip meristem.
Why are root tips placed in hcl
Students may also wish to carry out further investigations using plants such as hyacinth, onion and broad bean: details for producing root tip squashes for these are also given. Put in a small volume of ethanoic acid on a watchglass or other shallow dish for 10 minutes. Set up some roots to sprout 10 days before use, some 5 days before use, some 2 and some 1 day before use so that students can compare the rate of mitosis in young and older root tips. Heather Scoville is a high school science teacher and writes science curriculum for online science courses. Stage Observed occurrence in representative microscope fields Duration. Do not let the root dry out. For convenience, we will use garlic and onion because they are found in almost every household. Describe how you determined which phase each cell was in. Dissolve 0. Materials include: Tested materials to support the A-level practical endorsement CPAC Support materials for teachers and technicians Student worksheet to help provide evidence for meeting the practical skills requirements Student revision materials to help prepare for exams Support materials for other key practicals in A-level specifications can be found on the A-level set practicals main page. At any rate, garlic and onion are both liliaceae and their mitotic processes are very similar. We recommend using garlic for the standard practical. This procedure of maceration that permits the disassociation of the cells of the vegetable tissues, can also be tried for other reasons. Chromosomes in root tip tissue are made visible with the stain. Any light microscope that can magnify at least 40x is sufficient and can be used to complete this lab.
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