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Difference Between Yeast and Bacteria

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Are you someone who feels confused differentiating Bacteria from Yeast? In that case, you’ll just need to walk through this article right now.

What are the differences between Bacteria and Yeast?

Although both Bacteria and Yeast are unicellular microorganisms, there exists a number of elements that set them apart. From family to organization, from shape to size, almost everything sits differently in both. While we’ve Bacteria from the Monera family, Yeast is a fungus.

When viewed under a microscope, Yeast appears more like an oval; on the other hand, Bacteria resemble a rod to some extent. Apart from all these, there are other distinguishing actors; read along to learn more.

What are Bacteria?

Bacteria are uni celled microbes. These are the organisms that are not visible to the naked eye. Bacteria can be useful and harmful at the same time. These organisms were among the first life forms to make an appearance on mother earth and are still present around us in various forms.

Bacteria have our common forms, namely,

Coccus bacteria under microscope
Coccus bacteria under microscope
  • Coccus form
  • Bacillus form
  • Spirilla form
  • Vibrio form

What is a Yeast?

To put it in simple words, Yeast is a uni celled fungus. These are also microorganisms and are impossible to get viewed by the naked eye. Just like most of the other members of fungi, Yeast needs food, moisture, and heat to grow. Although used in the production process of beer, bread, and various types of antibiotics, these microorganisms can also adversely affect your health. Pretty similar to bacteria, Yeast also has four general types. 

  • Baker’s Yeast
  • Nutritional Yeast
  • Brewer’s Yeast
  • Distiller’s and Wine Yeast
Bakers yeast under microscope
Baker's yeast under microscope

Difference Between Bacteria and Yeast


Bacteria are categorized as Prokaryotes, while Yeasts are graded as Eukaryotes.


Bacteria belong to the Monera family. On the other hand, Yeast is listed among the family members of Fungi.

Shape and Size

When viewed under a microscope, bacteria appear to be either spherical or rod-shaped. They are typically small cells that are arranged in clusters. Yeast, on the other hand, is comparatively larger and resembles the shape of an oval.

Cell Wall

The composition of cell walls in both bacteria and Yeast is pretty different, where the one for bacteria is made up of murein, the same for Yeast is composed of chitin.

Availability of Nucleus

In the case of Yeast, each cell comprises a nucleus. On the other hand, the nucleus is entirely absent in bacteria.

Availability of Membrane-Bound Organelles

Bacteria lack any kind of membrane-bound organelles, while the same can’t be said for Yeast. These are indeed composed of mitochondria, lysosomes, Golgi apparatus, and other types of membrane-based organelles.


Yeast’s DNA is all about linear chromosomes. On the contrary, the DNA of bacteria features single cellular chromosomes.

Process of Respiration

Bacteria respire either via a method of aerobic or anaerobic respiration. The same process in Yeast involves Ethanol fermentation.


Bacteria have the 70S Ribosomes, where yeasts have the 80S ones.

Availability of Pili

While bacteria might contain pili, it is entirely absent in Yeast. If you’re wondering what pili actually is, let’s get a quick idea. Pili is a term for the shorter filaments of the protein named pilin. These generally emerge from the very cytoplasmic membrane.


Bacteria are mobile. They tend to make their movements with the help of flagella. However, yeasts are totally immobile.

Process of Reproduction

Yeasts continue with the process of reproduction by a process known as budding. Bacteria, on the contrary, multiply by binary fission.

Optimal pH Value

The pH value is again a differentiating factor between Bacteria and Yeast. At the same time, the former has a pH value that lies between 6.5 to 7, the same for the latter sticks somewhere within 4 to 4.6.


The role of Bacteria is immense in the production of various kinds of antibiotics. Alongside, these microorganisms are helpful in synthesizing various chemicals. Yeast, on the other hand, assists in manufacturing beer, bread, and other notable things.

Diseases Caused

Direct or indirect contact with harmful Bacteria might lead to various diseases like Pneumonia, TB, Cholera, tetanus, and more. When we talk about the diseases caused by Yeast, on the other hand, we’ve mycosis, vaginal infections, candidiasis, among the more frequent ones.

Comparison Chart: Bacteria Vs Yeast

Shape and SizeRod shaped (Smaller)Oval (Comparatively bigger)
Cell Wall CompositionMureinChitin
Availability of NucleusUnavailableOne per cell
Availability of Membrane Bound OrganellesUnavailableAvailable
DNASingle circular chromosomeLinear chromosome
Process of RespirationAerobic or anaerobicEthanol fermentation
Availability of PiliAvailableUnavailable
ReproductionBinary fissionBudding
pH Value6.5-74-4.6
UsageProduction of useful chemicalsProduction of bread, beer, and more
Diseases CausedTB, Cholera, Pneumonia, tetanus, etc.Mycosis, Candidiasis, vaginal infection

Similarities: How are Bacteria similar to Yeast


Both Bacteria and Yeast are unicellular microorganisms.

Process of Digestion

Whether we talk about Bacteria, or Yeast both undergo extracellular digestion.

Production of Antibiotic

Although Bacteria and Yeast have usage properties that extend in different directions, one thing that sits similar in both is their significance in the production of antibiotics.


Other factors that make Bacteria and Yeast reside under the same roof include the fact that both are heterotrophs, which means they derive nutrition from various complex organic substances.

Frequently Asked Questions

Which is bigger Bacteria vs. Yeast?

Although the size of Yeasts varies, they are usually larger when compared to the bacterial cells. This is one of the reasons why they are the members of higher-level microorganisms, popularly known as fungi.

Which are more harmful, Bacteria vs. Yeast?

Both Bacteria and Yeast can harm your body in different ways. While the former holds the prime reason for causing various diseases including TB, Cholera, tetanus, and more, Yeast can cause vaginal infections, mycosis, and even candidiasis.


Bacteria and Yeast both are microorganisms with different build and characteristics altogether. In this article, we’ve discussed most of the factors that help you place both the unicellular organisms in distinct boxes. Do you have more to look at? Make sure to let us know.


Feel free to comment and discuss about the article in the comment space below if you have any information or remarks to add. If you think we made a mistake, you can also report it there.
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About the Author: Nicolas Seignette

Nicolas Seignette, who holds a scientific baccalaureate, began his studies in mathematics and computer science applied to human and social sciences (MIASHS). He then continued his university studies with a DEUST WMI (Webmaster and Internet professions) at the University of Limoges before finishing his course with a professional license specialized in the IT professions. On 10Differences, he is in charge of the research and the writing of the articles concerning technology, sciences and mathematics.
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