Question

describe an experiment to observe cells in an onion peel and record your findings​

Answer 1

Answer:

Experiment:

Objective:

To prepare a stained temporary mount of human cheek cells and to record observations and draw labelled diagrams

Apparatus and materials required:

Toothpick, slide, coverslip, filter paper, needles, brush, watch glass, methylene blue, dropper, glycerin, water and a compound microscope

Theory:

Animal cells are usually irregular in shape. They do not have a cell wall. They are surrounded by a cell membrane and contain cytoplasm and nucleus.

Procedure:

1. With the help of the flat end of a washed toothpick gently scrape the inside of your cheek.

2. Place the scrapings in the centre of a clean glass slide.

3. Add a drop of water arid a drop of methylene blue.

4. After one minute remove the extra water mixed with methylene blue by slightly tilting the slide.

5. Put a drop of glycerine over the stained scrapings and cover it gently with a coverslip.

6. Remove the excessive glycerine using filter paper.

7. Observe the scrapings under the low and high magnifications of a microscope.

Observations:

(a) Removing Epithelial Cells from the Buccal Cavity using a Toothpick (b) Cheek Cells as seen under a Microscope

Many flat, oval or irregular cells are seen. The cell membrane encloses hyaline cytoplasm and an oval, dense nucleus. The cell wall is absent as in all animal cells.

Precautions:

1. The cheeks should be scraped gently avoiding any injury.

2. Over-staining and under-staining of the cells should be avoided.

3. Coverslip should be placed carefully avoiding the entry of air bubbles.

4. A dry and clean glass slide and coverslip should be used.

5. The cheek cells should be spread properly to avoid their folding.