CHAPTER 14 Ten Basic Experiments 85
add a drop of it to the slide. It helps to visualize the cell structures.
Better wear gloves to do so, as methylene blue is toxic if ingested.
Place
the coverslip onto the slide. There should be no air or bubbles!
And that’s it – have fun investigating the structures under your micro-
scope. Start with lowest magnification, and you will see:
✔✔Rectangular cells
✔✔Cell walls surrounding the cells
✔✔Dark stained nuclei containing the genetic material (DNA)
✔✔Vacuoles (cell organelles filled with water and many organic or
inorganic substances) in the center
✔✔Small granules inside the cells within the cytoplasm (containing
reserve substances to be stored like starch)
Cheek Cell Swabs
Have a look at your own body tissue by investigating your cheek cells. Scary, isn’t
it?! By the way, the correct name for these cheek cells is squamous epithelium
cells and they are used, for example, to test whether you have multi-resistant bacteria
before you undergo surgery.
You need:
✔✔A glass slide with coverslip
✔✔A Q-tip or toothpick
✔✔Methylene blue
✔✔Gloves
Scrape the inside of your cheek with the Q-tip or toothpick. Attention –
do not hurt yourself. This is not about preparing a blood smear. Wipe
the Q-tip or toothpick on to the center of the slide. Gently wipe the
edge of the coverslip over the scrapings. What you’re doing is called
a smear. A smear helps to get a sample layer thin enough to view it
clearly under a microscope. Drink a pot of tea and leave the smear to
dry. When the smear is dry, add a drop of methylene blue. Better wear
gloves to do so, as methylene blue is toxic if ingested. This stain helps