SEMESTER 1 PRACTICAL SCIENCE 1 EXPERIMENT 1 Topic Purpose : : Histology of Plant and Animal Cells

1. To prepare slides of animal cell and plant cells using the correct staining technique. 2. To realize that cell ia s basic unit of life. Statement to problem Material/Apparatus : i) ii) iii) iv) v) vi) vii) viii) ix) Microscope Toothpick Microscope slide Coverslip Dropper Forceps Methylene blue Iodine solution Onion : To determine the histology of plant cell and animal cell.

Procedure

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(a) Observation of animal cells. 1. Using a toothpick gently scrape off the thin layer of cells from the inside of your cheek. 2. Mount the scrapings in a drop of methylene blue solution on a slide.

3. Examine the specimen under low power objective lens followed by high power objective lens. 4. Draw the cheek cells and label the following parts : nucleus, nuclear membrane, chromatin granules, cell membrane, and cytoplasm. (a) Observation of plant cells. 1. Using a pair of forceps, peel off the epidermis layer of onion scale leaf. 2. Mount the epidermal layer in a drop of water on a slide. 3. Examine the specimen under the microscope. 4. Stain the onion scale leaf epidermis with iodine solution. Then examine the specimen under the microscope. 5. Draw the onion scale leaf epidermal cells. Label the cell wall, cell membrane, cytoplasm, nucleus, chromosome, nucleolus, and vacuole.

Results/Observations Onion cells

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Cheek cells

Discussion 1.

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Human cheek cells do not have a fixed shape but plant cell do have a fixed shape.

2. The methylene blue solution stains the cytoplasm and nucleus brown and the cytoplasm yellow. The iodine solution stains the nucleus brown and the starch granules and chloroplast blue black.. 3. Onion cell does not contain chloroplast and the cheek cells do not contain starch granules. Therefore, the iodine solution does not stain the cells blue-black. 4. The cellular components of plant cell that can be seen under the light microscope are the cell wall, nucleus, cytoplasm and vacuoles. 5. The cellular components of animal cell that can be seen under the light microscope are the plasma membrane, cytoplasm and nucleus. 6. Both plant cells and animal cells have a plasma membrane, cytoplasm and nucleus. 7. However cheek cells do not have a large vacuole and cell wall like onion cells.

Conclusion

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A typical plant cell has a fixed shape, a cell wall,a nucleus, a large vacuole, a plasma membrane, and cytoplasm. Plant cells have chloroplast needed for the process of photosynthesis. A typical animal cell does not have a fixed shape. It does have it has a nucleus, cytoplasm and a plasma membrane like a plant cells.