Yeast is something most of us relate to baking. A lot of us think of it as the substance we add to doughs to make them rise.
Or there are those of us who think about yeast infections when we hear the word yeast.
However, yeast is so much more than these ideas it has been reduced to.
A great way to discover more about yeast is to look at it under the microscope.
If you are curious about yeast and what yeast cells are like under the microscope, then you’ve come to the right place.
In this guide, we are going to walk you through what yeast is, its main characteristics, the habitats it can be found in, and fun observations.
What Is Yeast?
Yeast are single-celled microorganisms (Eukaryota) that are a part of the Fungus Kingdom. There are many different species of yeast, with over 1500 identified.
Yeast is classified under the phyla Ascomycota or sac fungi, and phylum Basidiomycota or higher fungi.
As mentioned before, yeast is known for a lot of things. It is known for aiding in fermentation and is it is known for being the cause of different types of infections.
Interestingly, yeast are primarily asexual organisms. Yeast also survives on substances such as organic sugars.
Yeast cells mainly reproduce in a particular way, however, there are some cases of sexual reproduction with yeast.
What Does Yeast Do?
Yeast is often considered to be incredibly useful to us. Many of the species of yeast are deemed as useful in some way. Different species of yeast are used in baking, making alcoholic drinks.
For these processes, different types of yeast are used such as baker’s yeast compared to a distiller’s yeast.
When yeast is used in baking or making drinks, it is used for the fermentation process. In order to ferment the yeast, it is fed sugar.
When the yeast is fed the sugar it is able to produce ethanol and carbon dioxide. However, it should be noted that not all species of yeast can be used in baking as some are harmful such as Candida albicans.
The process of fermentation for baked goods and alcoholic beverages is quite similar but there are some differences. For baking bread or pizza dough, the yeast feeds off of the sugars in the flour.
Then it produces carbon dioxide and ethanol. The ethanol is evaporated and carbon dioxide is what remains. It is this carbon dioxide which causes baked goods to rise.
For alcohol, the process is slightly different. Instead of finding sugar in the flour, cereals are added for the sugar. As the process of fermentation occurs, carbon dioxide and ethanol are produced.
Instead of the carbon dioxide and ethanol being evaporated, they are trapped in the drink which makes the drink alcoholic and fizzy.
Natural Habitats
Since there are so many species of yeast, there are plenty of different habitats they can be found in naturally.
One thing to consider when looking for yeast in its natural habitat is to look for a place where there is a lot of sugars.
Yeast cells are often found on plant leaves, fruits, flowers, skin, soils, animals intestinal tracts and even some deep-sea environments.
Yeast are able to survive in a lot of different environments, however the environment needs to be moist. In these environments, there must be simple and soluble nutrients for the yeast to grow and reproduce.
The Process Of Yeast Reproduction
Yeast cells undergo reproduction through asexual processes. The two main asexual reproduction process that yeast cells go through are budding and binary fission.
Budding
Budding is the process where a new cell is formed through mitotic cell division. The parent yeast cell or the old cell, produces a growth that is identical to the original cell.
This growth is called a bud. The bud stays attached to the old cell until the bud is independent. Once the bud is independent it splits away from the old cell.
Binary Fission
Unlike the budding process, during binary fission a new bud is not created. Instead, mitosis occurs and the genome replicates and divides.
Then a new plasma membrane is formed and the cell splits into two.
How To Observe Yeast
Now that you know more about yeast cells, the fun starts with observing them. Yeast cells can be observed under a microscope.
Yeast cells are very small as they have an average diameter of 5 to 10 micrometers. Therefore, when observing them under a microscope, they need to be viewed under a high magnification microscope.
There are two different microscopy techniques that can be used for yeast. These are Brightfield microscopy and Fluorescence microscopy.
Brightfield Microscopy
Yeast cells and buds can be seen under a 1000x magnification Brightfield microscope. When observing yeast cells under this microscope, you can expect to see oval or egg-shaped organisms.
These would be the yeast cells. Under this microscope, you might even be able to see the buds.
If the solution you are using also has sugar in it, then there might be bubbles present when you look under the microscope. This is the fermentation process you are observing.
Fluorescence Microscopy
If you want to take a closer look at the organelles inside yeast cells, then using the fluorescence microscopy technique can achieve that.
This method is often more beneficial for students as they are able to observe and identify the cell structure of yeast cells.
Although this method is quite difficult as yeast cells are incredibly small. This is why the use of different dyes has been developed to observe the different parts of a yeast cell.
Preparing Your Sample
Now you are of the different methods for observing yeast cells, it is important to make sure that you properly prepare your sample for the slide.
The easiest way to observe yeast is by going to the bakery and getting a yeast cake which is cultivated yeast. Alternatively, you can use some active yeast and add sugar to it.
Regardless of which one you choose, you need to make sure that it is mixed with water to make a paste.
When mixing a bit of the yeast cake with water, you should add sugar to it until it has dissolved. Let the yeast mixture stand for at least an hour before putting it on your slide.
Dyeing Yeast Cells
As mentioned before, one of the ways to observe yeast cells is by using dye to stain them. Dyes can be used to make different parts of the yeast cells more visible under the microscope.
There are many different dyes to choose from such as methylene blue.
Other dyes will help to see a particular part of the yeast cells. DAPI helps to make the nuclei of the cells more visible. DIOC6 can be used for the endoplasmic reticulum and the mitochondria.
FM4-64 is used for the vacuoles. Calcofluor White stains the cell walls of the yeast cells. DASPMI is used to make the mitochondria more visible.
However, whichever dye you choose to stain the yeast cells there are different methods for using each dye.
It is important to research the dye you plan to use, in order to make sure you are correctly staining them.
Observation
One of the things you might observe under the microscope is the fermentation process. This is easily identified as you will see bubbles.
It is also possible to observe the asexual repoduction process of budding. This is another process that is easily identified under the microscope.
When you see this process, you will notice that there is a smaller growth on the yeast cells you are observing. Since the budding process is quick, you can also observe the cells splitting.
Final Thoughts
To conclude, yeast cells which are part of the Fungus Kingdom, are great for observing under the microscope.
Under the microscope, it is possible to observe some of the amazing processes that yeast cells go through such as budding and fermentation.
Observing yeast cells under the microscope with the assistance of different dyes to stain the cells will help make them more visible.
This is ideal for becoming more familiar with yeast cells and what the structure of the cells look like.
We hope that this guide has helped you with all the information you need in order to observe yeast cells under the microscope.
Please share this guide with others it might benefit. Thank you for reading.
Ever since I was a little girl, I have been fascinated by science. Every holiday I would ask for the newest science kit, and spend weeks learning with it.
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