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Shania Littel
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The onion peel skin experiment allows students to view real plants cells under a microscope. This experiment is conducted by firstly peeling a small section of the thin membrane from a piece of onion. This piece of membrane will then be placed on a microscope with a drop of water to prevent the cells drying out, followed by the addition of Iodine solution which will stain the cells to make them visible. A thin glass slip will then be added, and once these steps have all been completed the students will be able to view the cells under a microscope.
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As mentioned above, in the reply from Paula, the process is straightforward. Her method works well. In an examination question, it is worth adding the following 2 points :
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Click here to view my profile and arrange a free introduction.Firstly Cut open an onion. Then use forceps to peel a thin layer of epidermis from the inside. Further lay the layer of epidermis on a microscope slide. Then add a drop of iodine solution to the layer. Carefully place a coverslip over the layer.
At last observe it under a microscope to see onion cells.
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From now you can use the fine focusing wheel to focus more precisely and increase the magnification by changing the objective lens to a higher number as required. You may need to re-focus with the fine focusing wheel when you do this.
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Click here to view my profile and arrange a free introduction.Peel off a leaf from half a piece of onion and using the forceps, pull out a piece of transparent onion peel (epidermis) from the leaf. Put the epidermis in the watch glass containing distilled water. Take a few drops of safranin solution in a dropper and transfer this into another watch glass.
Here's how to conduct the onion peel skin experiment in a few steps:
take a cutting that is 1 cell thin dye with methly-blue or iodine, place on glass slide with cover slip and use the microscope to look at the sample
When using onion skin to look at the cells under a microscope, the first thing you need to cut a small sample of onion using a scalpel. After this separate, the sections of onion and with tweezers remove a thin layer of onion skin. Place the onion skin onto a microscope slide and place 2 drops of iodine solutions (stain) on the onion skin (this allows you to see the cells). Carefully lower a cover slip on the sample. Place the slide on the base of the microscope and start on the lowest magnification (widest view). Focus until cells are found and then move up to the next objective lens.
I would help her by peeling the skin of onion and disected part would be examined by the help of compound microscope
This is a great experiment to view plant cells and practice your specimen staining skills. Firstly, you need to get together your materials:
Start by taking a small section of onion and peel off a thin layer of skin using forceps. Lie the tissue flat on the slide and add a drop of iodine solution. Slowly place on the coverslip to avoid air bubbles. Place the slide underneath the microscope at the objective lens and slowly work up to a higher objective lens by focusing using the course and fine focus.
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Carefully cut an onion into sections using a sharp knife or scalpel. Place a drop or two of Iodine solution onto a clean microscope slide. Using tweezers, remove the thin layer of skin from the underside of the onion, taking care not to twist or fold it. Place it on the Iodine solution. Hold a cover slip at an angle less than 90 degrees to the slide, in the Iodine solution, and allow it to meet the slide. In this way you will have hopefully removed any air bubbles and under the microscope will be able to clearly see the cell walls that have been stained brown.
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Click here to view my profile and arrange a free introduction.Presence of large vacuoles and cell wall confirms that cells of onion peel are plant cells. Take a piece of onion and bend it to remove the transparent membranous structure called onion epidermal peel.
1. Use a dropping pipette to put one drop of water onto a microscope slide.
2. Peel off a thin layer of epidermal tissue from the inner surface.
3. Use forceps to put this thin layer on to the drop of water that you have placed on the microscope slide.
4. Put two drops of iodine solution onto the onion tissue.
5. Carefully lower a coverslip onto the slide. Do this by:
• placing one edge of the coverslip on the slide
• use the forceps to lower the other edge onto the slide
6. Put the slide on the microscope stage.
Peel one layer of the onion skin and place the the skin on a microscope slide. Then, put a drop of iodine on the onion skin and place the slide under a microscope. Set the microscope to the lowest magnification and observe the cell structure. You should be able to see the nucleus of the cell.
This is the method for the GCSE Biology required practical:
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