Human Cheek Cell Exp

 

LESSON PLAN CLASS :IX (PRACTICAL)

SUBJECT: SUBJECT: BIOLOGY

NAME OF THE TEACHER: Ms Archna Verma AIM /OBJECTIVE OF ACTIVITY: ACTIVITY: To Prepare Stained Temporary Mount of Human Cheek Cells THEORY: Human Cheek Cell  As in all animal cells, the cells of the human cheek do not possess a cell wall. A cell membrane that is semi-permeable surrounds the cytoplasm. Unlike plant cells, the cytoplasm in an animal cell is denser, granular and occupies a larger space. The vacuole in an an animal cell is smaller in size, or absent. The nucleus is present at the centre of the cytoplasm.The absence of a cell wall and a prominent vacuole are indicators that help identify animal cells, such as cells seen in the human cheek.

.Materials Required: Slide, cover slip, methylene blue, glycerine, toothpick, dropper and microscope. Lab Procedure  

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Gently scrape the inner side of the cheek using a toothpick, which will collect some cheek cells. Place the cells on a glass slide that has water on it. Mix the water and the cheek cells cells using a needle and spread spread them. Take a few drops of Methylene blue solution using a dropper and add this to the mixture on the slide.  After 2-3 minutes remove any excess water and stain from the slide using a blotting paper. Take a few drops of glycerine using a dropper and add this to the test mixture. Take a clean cover slip and lower it carefully on the mixture with the aid of a needle. Using a brush and needle, press the cover slip gently to spread the epithelial cells. Remove any extra liquid around the cover slip using a blotting paper. Place this glass side on the stage of the compound microscope and view it.

 

Observations    A large number number of flat and irregular-shaped irregular-shaped cells cells are observed. observed.   The cells do not have a cell wall. However, each cell has a thin cell membrane.    A deeply stained stained nucleus is observed observed at the centre centre of each cell cell..   No prominent vacuoles are observed in the cells.   Large irregularly shaped cells with distinct cell walls.    A distinct nucleu nucleus s at the central part of of each indiv individual idual cell (dark blue blue in color).

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   A lightly stained cytoplasm in each each cell.

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Conclusion  As the cells observed do not have a cell wall, nor a prominent vacuole, the cells of the specimen on the slide are animal cells.

 

OBSERVATION SHEET: The Human Cheek Cell Sketch the cell at low and high power. Label the nucleus, cytoplasm, and cell membrane of a single cell. cell. Draw your cells to scale.

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High Power

2. Why is methylene blue necessary? 3. The light microscope used in the lab is not powerful enough to view other organelles in the cheek cell. What parts of the cell were visible.

4. List 2 organelles that were NOT visible but should have been in the cheek cell. 5. Is the cheek cell a eukaryote or prokaryote? How do you know? 6. Keeping in mind that the mouth is the first f irst site of chemical digestion in a human. Your saliva starts the process of breaking down the food you eat. Keeping this in mind, what organelle do you think would be numerous inside the cells of your mouth?