To exemplify the theme of fungi and fermentation, the teacher can conduct a practical class with the yeast cell under the microscope.
Bread yeast is formed by enzymes – single-celled fungi of the species Saccharomyces cerevisiae. This yeast is responsible for making bread dough and other products lighter and softer thanks to its ability to carry out the so-called alcoholic fermentation.
In alcoholic fermentation, glucose is degraded, and alcohol and carbon dioxide are produced. It is the carbon dioxide that accumulates in the mass and expands it; that is, it leaves it much more extensive than its initial volume.
In this lesson proposal, we will analyze the yeast cell in the microscopic. See below the material necessary for its realization:
- Bread baking;
- Warm water;
- Gentian violet;
- Bunsen burner or other material that provides a flame.
First, the bread yeast should be dissolved in warm water. After this procedure, add sugar and wait for about 15 to 20 minutes. Take a drop of the prepared material, place it on the slide and cover it with a coverslip to observe the yeast cell.
After drawing the observed image and writing down the analyzed results, start manufacturing a new slide. For this blade, you must place a drop of the material and pass it over a flame so that the material dries and is fixed.
Place the gentian violet dye on the slide and wait five minutes. After staining, wash the slide under running water quickly, cover the slide with the coverslip, and analyze again yeast under the microscope. All layouts must be carried out.