Difference between Eubacteria and Archaebacteria

Both Eubacteria and Archaebacteria and are single celled prokaryotic microorganisms without a true nucleus and membrane bound organelles.

15 Difference between Eubacteria and Archaebacteria



Eubacteria are called “true bacteria”.

Large group of bacteria with rigid cell walls, flagella, single circular DNA distinct from archaea

Archaea are called “ancient bacteria”.

It is considered to be an ancient form of life that evolved separately from bacteria and blue-green algae distinct from eubacteria

Found almost everywhere on Earth.

Fresh water, salt water, swamps, human guts etc.

Mostly grows in extremely harsh environments therefore called as extremophiles. Archaea that lives in high acidic environment (acidophiles) high temperature (Thermophiles), high salinity (halophiles) and methane producing methanogens). Now, known to live everywhere, in ocean floor to the cow gut.


Peptidoglycan Cell wall made up of

N-acetylglucosamine (NAG) and N-acetylmuramic acid cross-linked via short peptide bridges


Cell wall composed of various polysaccharides and glycoconjugates

In some archaea Pseudomurein is present: Instead of NAM, it contains N-acetylalosaminuronic acid (NAT) linked to NAG, with peptide bridges


Plasma membrane: Eubacteria have D-glycerol

Glycerol connected to branched chain by ester linkage

Side chains are unbranched and made up of fatty acids


Archaean's plasma membrane have L-glycerol

Glycerol connected to branched chain by ether linkage

Side chains are branched and made up of Isoprene units


70S ribosome.

Sensitive to antibiotics that inhibit ribosomal function in bacteria.


70S ribosome. But Archaeal ribosomes have a different shape and different protein composition

This provides them with resistance to antibiotics that inhibit ribosomal function in Eubacteria.


Single RNA polymerase made up 5 subunits


Single RNA polymerase made up 11~13 subunits depending on the species.

Similar to the eukaryotic RNA Polymerase II

Watch our video for better understanding

Antibiotic sensitivity: Sensitive to antibiotics.

Most eubacteria are sensitive to penicillin because the antibiotic inhibits synthesis of peptidoglycan

Archaebacteria is insensitive to many antibiotics acting against eubacteria as cell wall lacks peptidoglycan. Susceptible to the protein synthesis inhibitor fusidic acid and imidazole derivatives.

Photosynthesis: Cyanobacteria are photosynthetic eubacteria, with ability to evolve oxygen. Bacteriochlorophyll is involved

Oxygen–evolving photosynthesis is absent.


Bacteriochlorophyll is involved in Photosynthesis

In Halobacteria, bacteriorhodopsin is involved in photosynthesis

Methanogenesis absent in eubacteria

Methanogens that produce methane from carbon dioxide as a metabolic by-product.

The initiator tRNA of protein synthesis is formylated methionine tRNAfMet

The initiator tRNA is tRNAMet; not formylated just like eukaryotes

Capsule; an outer layer of polysaccharides that covers the cells of many eubacterial species.

Capsule rare or absent.

Hami and Cannulae absent


Hami and Cannulae present.

Hamus is an archaeal cell surface appendage; a long helical tube with three nano hooks at the far end.

Cannulae: hollow tube-like structures appear to connect cells after division forming network of cells


Escherichia coli

Streptococcus pyogenes

Lactobacillus acidophilus


Halobacterium salinarum

Salinibacter ruber

Methanococcus Jannaschii

Aeropyrum pernix

Perras, A. K., Wanner, G., Klingl, A., Mora, M., Auerbach, A. K., Heinz, V., ... & Moissl-Eichinger, C. (2014). Grappling archaea: ultrastructural analyses of an uncultivated, cold-loving archaeon, and its biofilm. Frontiers in microbiology, 5, 397

Moissl C, Rachel R, Briegel A, Engelhardt H, Huber R. The unique structure of archaeal 'hami', highly complex cell appendages with nano-grappling hooks. Mol Microbiol. 2005 Apr;56(2):361-70. 

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