lab activity of observing nucleus in onion peel cells full format
Answers
*put a drop of water on a glass slide.
*place a small piece of neatly cut peel on it.
*put a drop, or two, of saffranin.
*stain for a minute.
*put a cover slip and observe in under the microscope.
You will see that the cells here are arranged in rows. observe their boundaries. there in a dark structure in the centre of each cell. it is the nucleus.
Explanation:
Aim : To observe the nucleus in cheek cells.
Material: A tooth pick or ice-cream spoon or spatula, glass slide, coverslip, watch glass, needle, blotting paper, 1% methylene blue, normal saline, glycerine, microscope etc.
Procedure:
1. Wash your mouth and scrap a little of the internal living of your cheek inside your mouth with a clean tooth pick or spatula or ice-cream spoon.
2. Place the scrap in a watch glass containing a very small quantity of normal saline.
3. Then place the material on a glass slide.
4. Put a drop of methylene blue and wait for a couple of minutes.
5. Wipe off the extra stain with a fine cloth of blotting paper.
6. Put a drop of glycerine over it.
7. Place a coverslip. Tap the coverslip with the blunt end of needle so as to spread the cells.
Precautions :
1. Do not scrap the cheek too hard as it may injure the buccal mucosa.
2. Scrapped material should be spread uniformly on the slide.
3. Excess stains should be drained off.
4. There should be no air bubbles under the coverslip.
Observations :
1. The shape of the cells are circular in shape.
2. These cells are not similar to the structure in onion peel cell.
3. Near the centre of the cell there is a darkly coloured oval dot like structure present.
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