Elodea and Cheek Cells Lab Report
DESIGN
Question: Where lie the differences between plant cells and animal cells using the example of Elodea and cheek cells?
Hypothesis: Based on the fact that plant cells have a cell wall, the elodea may look more structured, whereas the cheek cells who only have a membrane surrounding them, may look more scattered in form. The elodea may appear larger than the cheek cells because plant cells have a larger vacuole than those of the animal cells.
Variables:
|
Independent |
Dependent |
Controlled |
|
Leaf of Elodea |
– |
Methylene Blue |
|
Cheek Cell |
– |
Drops of water |
Procedure:
Elodea Lab
• Make sure that your work area is clean and that all the materials are set up and organized.
• Using a pair of tweezers, collect a sample (leaf) from the elodea plant.
• Place carefully on the glass slide and put two drops of water on the sample.
• Place the coverslip onto the slide at a 45o angle.
• Place the slide under the microscope on low power and gradually move to high power.
• Draw what you can see.
Cheek Cell Lab
• Gently scrape the inside of your cheek using a toothpick.
• Put one drop of water on a clean glass slide and stir the toothpick in the water.
• Carefully put one drop of methylene blue on the slide. Note: Methylene Blue does stain skin and clothes.
• Place the coverslip onto the slide at a 45o angle.
• Place the slide under the microscope on low power and gradually move to high power.
• Draw what you can see.
DATA COLLECTION AND PROCESSING
Elodea Raw Data Cheek Cell Data
|
Length (+/- ́m) |
Width (+/- ́m) |
Length (+/-́m) |
Width (+/- ́m) | |
|
80 |
60 |
42 |
42 | |
|
210 |
105 |
35 |
40 | |
|
45.7 |
16 |
30 |
50 | |
|
60 |
35 |
60 |
46.7 | |
|
60 |
27.3 |
46.7 |
30 | |
|
84 |
40 |
47.8 |
45.6 | |
|
65 |
26.3 |
35.2 |
20.1 | |
|
52 |
42 |
56.3 |
27.4 | |
|
37.5 |
20.5 |
54.5 |
43.4 | |
|
80 |
60 |
32.4 |
33.3 | |
|
37.5 |
35.5 |
31.3 |
35 | |
|
110 |
53.3 |
57.1 |
45.7 | |
|
37.5 |
30.6 |
35 |
64.3 | |
|
75 |
45 |
40 |
60 | |
|
66.7 |
40 |
|||
|
Mean: 73.4 |
Mean: 42.4 |
Mean: 42.4 | ||
Elodea and Cheek Cells Lab Report
DESIGN
Question: Where lie the differences between plant cells and animal cells using the example of Elodea and cheek cells?
Hypothesis: Based on the fact that plant cells have a cell wall, the elodea may look more structured, whereas the cheek cells who only have a membrane surrounding them, may look more scattered in form. The elodea may appear larger than the cheek cells because plant cells have a larger vacuole than those of the animal cells.
Variables:
|
Independent |
Dependent |
Controlled |
|
Leaf of Elodea |
– |
Methylene Blue |
|
Cheek Cell |
– |
Drops of water |
Procedure:
Elodea Lab
• Make sure that your work area is clean and that all the materials are set up and organized.
• Using a pair of tweezers, collect a sample (leaf) from the elodea plant.
• Place carefully on the glass slide and put two drops of water on the sample.
• Place the coverslip onto the slide at a 45o angle.
• Place the slide under the microscope on low power and gradually move to high power.
• Draw what you can see.
Cheek Cell Lab
• Gently scrape the inside of your cheek using a toothpick.
• Put one drop of water on a clean glass slide and stir the toothpick in the water.
• Carefully put one drop of methylene blue on the slide. Note: Methylene Blue does stain skin and clothes.
• Place the coverslip onto the slide at a 45o angle.
• Place the slide under the microscope on low power and gradually move to high power.
• Draw what you can see.
DATA COLLECTION AND PROCESSING
Elodea Raw Data Cheek Cell Data
|
Length (+/- ́m) |
Width (+/- ́m) |
Length (+/-́m) |
Width (+/- ́m) | |
|
80 |
60 |
42 |
42 | |
|
210 |
105 |
35 |
40 | |
|
45.7 |
16 |
30 |
50 | |
|
60 |
35 |
60 |
46.7 | |
|
60 |
27.3 |
46.7 |
30 | |
|
84 |
40 |
47.8 |
45.6 | |
|
65 |
26.3 |
35.2 |
20.1 | |
|
52 |
42 |
56.3 |
27.4 | |
|
37.5 |
20.5 |
54.5 |
43.4 | |
|
80 |
60 |
32.4 |
33.3 | |
|
37.5 |
35.5 |
31.3 |
35 | |
|
110 |
53.3 |
57.1 |
45.7 | |
|
37.5 |
30.6 |
35 |
64.3 | |
|
75 |
45 |
40 |
60 | |
|
66.7 |
40 |
|||
|
Mean: 73.4 |
Mean: 42.4 |
Mean: 43.1 |
Mean: 41.7 | |
Sample Calculations
CONCLUSION & EVALUATION
Conclusion:
The data that was gathered from this experiment seems to support the hypothesis above, which states that the size of a plant cell is larger than that of an animal cell. The calculated averages help to show the size difference between the elodea (73.4 ́m in length) and the human cheek cell (43.1́m in length). The second part of the hypothesis can be supported by the diagrams for each cell. The elodea sample that was observed appeared to have a strong structure of cells, which could be compared to a brick wall in the way that the bricks align with one another. This is due to the fact that a plant cell contains both a cell membrane and a cell wall which help keep the cell rigid. On the other hand, the form of the cheek sample was more scattered which is most likely due to it not having a cell wall.
Limitations of Experimental Design:
I think that my experimental design helped support my hypothesis, in particular concerning the question of cell structures. Being able to view the sample under high power allowed for the design to be accurate and detailed. A limitation could be the scale at which I drew the design. Had I drawn it more zoomed in, few cells would have been portrayed with greater detail perhaps. However, I think that this scale allows for a larger picture and shows more of the structure of the elodea. Another possible limitation was the fact that the raw cheek cell data contains one value less than the data for the elodea. This is due to an experimental mistake caused by a structure that was recorded as being a cheek cell but turned out otherwise. This may limit the accuracy of the data because there is not an equal set to compare both.
Suggestions for Improvement:
If I was to do this investigation again, I would make sure to pay closer attention to the instructions given when it came to the size of the experimental design. Together as a group the class would also need to improve on our individual performance so that the results could be as accurate as possible and beneficial to everyone’s calculations.
Textbook Questions:
a) How does the arrangement of plant cells and animal cells differ?
Plant cells differ from animal cells in that they have a cell wall and a large central vacuole. Animal cells on the other hand, do not have a cell wall and instead of one large vacuole contain smaller ones. The cell wall provides the cell with the rigid balance it needs. Another difference between animal and plant cells are chloroplast. Chloroplast are small cell structures found on the inside which allow cells to make their own food through a process called photosynthesis. Animal cells cannot feed themselves thus they use the cell membrane to allow nutrients inside and let the waste get out.
c) Compare the elodea cells to the tomato cells. Explain why the cells of the tomato do not appear to have any chloroplasts.
Tomato cells do not appear to have any chloroplasts, because they convert to a similar structure called chromoplast once the fruit begins to ripen. Chloroplasts allow for the synthesis in a plant to take place and are what gives it the green pigment. Chromplasts give the fruit the pigment of yellow, orange and red. Tomatoes continue to contain to contain chloroplast in the leaves even after they are ripe.
e) What structures did the methylene blue stain in the plant tissue?
The methylene blue stained the nucleus and cytoplasm of the cheek cell.
g) What careers would make use of the techniques learned in this activity?
Careers that would make use of the techniques learned in this activity would include: Zoologist, Nature Conservator, Microbiologist, Marine Biologist, Horticulturist, Ecologist, and Biochemist.