Reagents required
- Methylene blue (1 in 100)
- Iodine
Should be available
- Laboratory coats
- Gloves
- Safety glasses
Safety Points
When using a light microscope we use the light form a lamp to brighten the microscope. We don't use the sun because it is too powerful, and if the naked eye looks at the sun for too long, the retina can be burnt. I should place the microscope in the middle of the table so that it doesn't slip off the sides. Make sure the lamp is away from anything that can be burnt.
Method
I positioned a cover slip on top of the epidermis, again making sure that it was kept flat. On one side of the cover slip I placed a drop of iodine solution, which was a suitable stain for the plant cells. I placed the cut edge of a piece of filter paper to the other side of the cover slip which would draw a small amount of stain beneath the cover slip. I placed the slide under the microscope carefully to look at the onion cell until I could see a clear image of the cells. Viewing with a microscope I looked at the slide through low power then followed by high.
Drawing
Cheek Cell Onion Cell
Measurement
The measurements for the solutions had to be perfect as to not change the out come of the experiment. I had to ensure that every time I handled the potatoes my hands were clean and dry. This was to stop any kind of contamination.
Analysis of Data
In our cheek cell experiment we have only used one dye to stain the cells which was the methylene blue. This obviously makes the parts of the cell harder to identify as the view is unclear. As different parts of the cell are stained different colours in the lab it also makes it easier to spot any changes.
Conclusion
From the results it is possible to identify the basic structures of the two different samples. It is clear from the two diagrams that both cells have the basic components of a cell.
Evaluation
This experiment was fair to me because we only needed to do once and no repeats. I could see the differences between the cheek cell and onion cell (see the drawing of the cells in the next page). However, it allowed me to see the nucleus. I could see dozens of cells through the microscope.
