Download Experiment : Cheek cell.

Experiment : Cheek cell.
AIM : To prepare stained temporary mount of human cheek cells and to record
observations and dram its labelled diagrams.
MATERIALS REQUIRED
Sterilised toothpick , watch glass, slide, coverslip, needle, forceps, brush dropper,
water, glycerine, methylene-blue stain, microscope, blotting/filter paper,
THEORY
An animal cell is surrounded by a semi-permeable cell membrane around the
cytoplasm. Cell wall is absent in animal cells . Human cheek cells are living and
contain dense and granular cytoplasm The vacuoles are smaller in size or absent in
animal cells. Nucleus lies in the centre of the cytoplasm.
PROCEDURE
1. Rinse the mouth with fresh water and disinfectant solution.
2. Take a clean sterilised toothpick. Gently scrap the inner side of your cheek to
collect some epithelial cells.
3. Take a clean glass slide. Put 1-2 drops of distilled water in the centre of the
slide. Transfer the scrapping to the centre of the slide and spread it with a
needle.
4. Add a drop of methylene blue stain.
5. Wait for 1-2 minutes so that cells become blue stained.
6. Place the coverslip carefully on it by using a needle, so that no air-bubbles
enter the slide.
7. Remove excess stain with blotting paper.
8. Focus the slide under the microscope under 10X magnification.
9. Record the observations.
OBSERVATIONS
1. Large number of flat and irregular-shaped cells are seen with a thin cell
membrane.
2. Each cell has a thin cell (plasma) membrane. Cell wall is absent.
3. A darkly stained nucleus lies in the centre of the cell.
4. Cytoplasm lies inside the cell membrane which is granular in appearance.
S. No
Character
Observation
1.
Shape of cell
Irregular shape
2.
Arrangement
Flat compactly arranged
3.
Inter cellular spaces
Absent
4.
Cell membrane
Prominent
5.
Cell wall
Absent
6.
Cytoplasm
Granular
7.
Nucleus
Prominent darkly stained in the centre
of cytoplasm.
8.
Vacuoles
Absent or very small.
RESULT
1. The cells observed under 10X magnification of microscope do not show cell wall and
large vacuoles.
2. The cells have nucleus in the centre of the granular cytoplasm.
3. The cytoplasm is surrounded by cell membrane.
4. Human cheek cells are flat, irregular in shape and without any inter cellular
spaces and are squamous epithelial type of animal tissue.
5. There are no inter cellular spaces in the cell.
PRECAUTIONS
1. Rinse the mouth with fresh water and disinfectant solution.
2. Clean toothpick should be taken for scrapping of cheek cells.
3. Scrape the inside of the cheek gently so that no injury is caused.
4. Use clean slide. Excess water should be removed from the slide with a blotting
paper
5. Place the coverslip carefully to avoid air bubbles.
6. Do not over stain the material.
(Draw on the left hand side page of your journal)
Human Cheek Cells (Squamous Epithelium)