Bacteria are one of the types of biological cells. A large category of prokaryotic microorganisms is bacteria.
The categories of bacteria are scientifically based on the nature of their cell walls and shapes. Few are categorized based on genetic makeup as well.
Belonging to the same prokaryotes family, based on their genetic makeup, there are two types available. One is the Archaea, and the other is the Eubacteria.
Key Takeaways
- Archaea are single-celled microorganisms that belong to the domain Archaea, characterized by unique genetic, biochemical, and structural features and an ability to survive in extreme environments.
- Eubacteria, also known as “true bacteria,” are single-celled organisms belonging to the domain Bacteria, exhibiting diverse shapes, sizes, and metabolic capabilities, inhabiting various environments.
- The primary distinction between archaea and eubacteria lies in their genetic, structural, and biochemical characteristics and their preferred habitats, with archaea being more adapted to extreme conditions and eubacteria being found in a wide range of environments.
Archaea vs Eubacteria
The difference between the Archaea and Eubacteria is that Archaea is a single-celled bacterium that thrives in extreme conditions, while eubacteria live and thrive in normal conditions. Archaea is the oldest bacteria ever known while the earth was formed.

Both Archaea and Eubacteria belong to the kingdom called Monera.
Comparison Table
Parameter of Comparison | Archaea | Eubacteria |
---|---|---|
Meaning/ Definition | Archaea are a type of bacteria that are single-celled and simple microorganisms that are capable of living and thriving in extreme conditions. They belong to the Monera Kingdom. | Eubacteria are a type of bacteria that are single-celled and complex microorganisms that are capable of living and thriving in normal conditions. They also belong to the Monera Kingdom. |
Places of existence | Archaea are widely found in very unusual environments. Ocean depth, volcanic sites, Salt brine. | Eubacteria are found almost everywhere. It is found in all living and non-living organisms, soil, water, etc. |
Reproduction | Archaea follows Asexual reproduction. This happens by binary fission, fragmentation, or at times by a budding process. | Eubacteria produces spores. This allows them to live in not-so-favourable conditions also. They reproduce Sexually as well as Asexually. |
Cell Wall | The cell wall is pseudo peptidoglycan. | The cell wall is made up of peptidoglycan with muramic acid or sometimes with lipopolysaccharide. |
Impact factor | Archaea are non-pathogens, meaning they are not harmful and never cause human diseases. | Eubacteria are pathogens, meaning they may cause diseases in humans. |
What is Archaea?
Archaea are single-celled and simple microorganisms that live and thrive in extreme conditions. They are extensively found in deep ocean beds, salt brine, and volcanic eruption sites.
They belong to the Monera Kingdom, and they are prokaryotes. Archaea are also commonly called extremophiles.
Archaea are of different shapes. A few are flat and square-shaped, while many are in the shapes of spirals, rods, plates, and spheres.
The cell wall of archaea is made of pseudo-peptidoglycan. Archaea have been observed to have lipids linked with ether with the branching of aliphatic acid.
The reproduction process of Archaea is carried out Asexually. The Asexual reproduction process is carried out by budding, fragmentation, or even the binary fission process.
There are three types of Archaea identified to date. They are Methanogens, Thermophiles, and Halophiles. Indeed, the archaea are non-pathogens.
Methanogens are widely used for wastewater treatment as it converts carbon dioxide and bacterial waste to methane. Likewise, thermophiles and halophiles have their uses in the human community.
The outer cellular layer, called the membrane, plays a vital role in archaea. They act as a barrier to the cell and the external environment, making them thrive very strongly in extreme environmental conditions.

What is Eubacteria?
Eubacteria are a type of bacteria that are single-celled and complex microorganisms that are capable of living and thriving in normal conditions. They are everywhere, like the soil, water, and living and non-living organisms.
Eubacteria also belong to the Monera kingdom, and they are also prokaryotes. Eubacteria are known as bacteria as well.
The cell wall of eubacteria is made up of peptidoglycan. Eubacteria has ester links with fatty acids. The shapes of Eubacteria are Spherical, rod, cocci, and spiral.
The bacteria are enclosed in an envelope that protects and regulates the transport of materials.
They reproduce sexually as well as asexually. They are capable of reproducing under unfavourable conditions too.
Eubacteria are pathogens, too, meaning they can be harmful and cause sickness in humans. As such, there are non-pathogenic eubacteria too.
Two types of Eubacteria exist. One is the gram-positive eubacteria, and the other is the gram-negative eubacteria.
Eubacteria follow the glycolysis pathway and Krebs’ cycle to produce energy. Thymine is present in the tRNA of the Eubacteria, whereas Introns are absent.

Main Differences Between Archaea and Eubacteria
- Archaea thrive in extreme conditions, whereas eubacteria can be found almost everywhere.
- Archaea reproduces Asexually through binary fission, fragmentation, and budding process, while Eubacteria reproduces Asexually and Sexually.
- Archaea are completely Non-Pathogens, while eubacteria have both pathogenic and non-pathogenic bacteria.
- The cell wall of Archaea is made up of Pseudopeptidoglycan as they also have ether bonds with aliphatic acid, while eubacteria have lipid membrane ester links with fatty acids.
- Archaea do not follow glycolysis or Kreb’s cycle for metabolic activities but follow a similar pathway, whereas Eubacteria follow glycolysis and Kreb’s cycle to break down glucose and produce energy.

- https://www.cell.com/trends/genetics/fulltext/S0168-9525(99)01966-6
- https://www.jstage.jst.go.jp/article/bpb/31/2/31_2_173/_article/-char/ja/
- https://www.pnas.org/content/93/3/1071.short
Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.