Due to their small size and prokaryotic cell structure, Eubacteria and Archaebacteria are two major domains of single-celled microorganisms that were previously classed as bacteria. However, as genetic and molecular research progressed, scientists found that they had significant differences that justified their division into independent realms.

EUBACTERIA

Eubacteria, often known as microorganisms, are a varied collection of single-celled microorganisms in the Bacteria domain. They are among the most numerous and widespread creatures on the planet, living in a variety of settings ranging from soil and water to the human body. Eubacteria are important in many ecological processes, such as nutrient cycling, decomposition, and symbiotic partnerships.

Eubacteria are prokaryotic, which means they do not have a genuine nucleus or organelles that are membrane-bound. Their genetic information is structured in a single circular chromosome found in the cell’s nucleoid region. The cell wall of Eubacteria is typically formed of peptidoglycan, a complex carbohydrate that gives structural support and protection to the cell. The composition of the cell wall varies between bacterial species. Eubacteria are classified into several morphologies, including cocci (spherical), bacilli (rod-shaped), spirilla (spiral-shaped), and others.

Eubacteria have a wide range of physiological capabilities. They can be autotrophic, meaning they get their energy from sunlight via photosynthesis (like cyanobacteria) or from inorganic substances via chemosynthesis. They can also be heterotrophic, meaning they get their energy from organic molecules.

Eubacteria reproduce largely through binary fission, which occurs when a single bacterial cell divides into two identical daughter cells. This quick reproduction helps the community grow and respond to changing conditions.

ARCHAEA

Archaea, commonly referred to as archaebacteria, are a class of single-celled microorganisms that were mistaken for bacteria due to their prokaryotic cell structure and tiny size. Significant genetic, biochemical, and ecological distinctions between archaea and microorganisms, however, have led scientists to designate them as distinct areas of life.

Archaea are well-known for their capacity to grow in harsh circumstances that include high temperatures, high salinity, alkaline or acidic conditions, and anaerobic (low-oxygen) conditions. They were identified in severe conditions such as hot springs and hydrothermal vents, but they have since been detected in soil, oceans, and animal digestive tracts.

Archaea have cell walls that lack peptidoglycan, a component found in bacteria’s cell walls. They may instead have unique compounds such as pseudopeptidoglycan or other specific structures.It cell walls are made up of lipids known as isoprenoids or ether lipids, which differ from the fatty acid-based lipids found in bacterial and eukaryotic cell membranes.

It possesses distinct genetic sequences and molecular machinery that distinguish them from bacteria and eukaryotes. Their genetic code, transcription, and translation processes can be markedly distinct from those of other creatures.

Here are 38 differences between Eubacteria and Archaebacteria:

S.No.	Aspect	Eubacteria	Archaebacteria
1	Domain	Bacteria (Bacteria domain)	Archaea (Archaea domain)
2	Cell Wall	Contains peptidoglycan in the cell wall	Lacks peptidoglycan in the cell wall
3	Lipid Bilayer	Typically have a phospholipid bilayer with fatty acids	Have ether-linked lipids in the bilayer
4	Membrane Lipids	Composed of glycerol-ester lipids	Composed of glycerol-ether lipids
5	Cell Membrane Function	Sensitive to antibiotics like penicillin	Resistant to many antibiotics
6	Extreme Environments	Generally not found in extreme environments	Often found in extreme environments
7	Methanogenesis	Lacks the ability for methanogenesis	Some can perform methanogenesis
8	Introns	Rarely contain introns in their genes	Introns are more common in their genes
9	RNA Polymerase	Typically have one type of RNA polymerase	Have multiple types of RNA polymerases
10	Histones	Generally lack histone proteins	Have histone-like proteins
11	RNA Processing	RNA processing is simple	RNA processing is more complex
12	Sensitivity to pH	Often sensitive to extreme pH conditions	Tolerant of extreme pH conditions
13	Sensitivity to Temperature	Wide temperature tolerance range	Can thrive in extreme temperatures
14	Oxygen Sensitivity	Some are anaerobic, while others are aerobic	Many are anaerobic
15	Extremophiles	Rarely extremophiles	Often extremophiles
16	Hydrothermal Vents	Not commonly found in hydrothermal vents	Often found in hydrothermal vents
17	Antibiotic Production	Some produce antibiotics	Few produce antibiotics
18	Cell Membrane Composition	Contains diacyl glycerol tetraethers	Contains diacyl glycerol diethers
19	Cell Wall Composition	Contains peptidoglycan or pseudopeptidoglycan	Lacks peptidoglycan
20	RNA Polymerase Sensitivity	Sensitive to rifampin antibiotic	Resistant to rifampin antibiotic
21	Antibiotic Target	Often targeted by antibiotics like streptomycin	Not typically targeted by common antibiotics
22	Genetic Transfer Mechanisms	Conjugation, transformation, transduction	Less well-defined genetic transfer mechanisms
23	Ribosome Sensitivity to Toxins	Sensitive to diphtheria toxin	Resistant to diphtheria toxin
24	Antibiotic Resistance Mechanisms	Common mechanisms include efflux pumps, mutations	Less common mechanisms for resistance
25	Circular DNA	Typically have a single circular chromosome	Usually have multiple circular chromosomes
26	Presence of Introns	Rarely contain introns in their genes	Introns are more common in their genes
27	Cell Wall Function	Provides structural support and shape	May serve structural or protective functions
28	Peptidoglycan Function	May provide resistance to osmotic stress	Not present, so no role in osmotic resistance
29	Methanogens	Rarely include methanogens among them	Often include methanogens among them
30	Ribosome Sensitivity to Toxins	Sensitive to antibiotics like chloramphenicol	Resistant to chloramphenicol antibiotic
31	Lipopolysaccharides	Present in Gram-negative bacteria	Not present
32	Pseudopeptidoglycan	Found in some groups, like Archaea Crenarchaeota	Not found in Archaebacteria
33	Endospore Formation	Some species can form endospores	Typically do not form endospores
34	Antibiotic Target	Common target for antibiotics like ampicillin	Not typically targeted by common antibiotics
35	Nucleotide Base Composition	Often have higher G+C content	Often have lower G+C content
36	Thermophiles	Some are thermophiles	Many are thermophiles
37	Biochemical Pathways	Have a wide range of metabolic pathways	Unique metabolic pathways
38	Archaeal Extremophiles	Found in extreme environments like hot springs	Often thrive in extreme environments

Also read: Active Immunity vs Passive Immunity – 26 Key Differences

Frequently Asked Questions (FAQ’s):

Q1. What kinds of Eubacteria are there?

Coli, Streptococcus, Staphylococcus, Bacillus, and Mycobacterium tuberculosis are typical examples of Eubacteria.

Q2. What is the process by which Eubacteria reproduce?

Eubacteria replicate through binary fission, in which a single bacterial cell splits into two identical daughter cells.

Q3. What role does Eubacteria play in the environment?

Eubacteria are important in several ecological processes, including nutrient cycling, breakdown, and nitrogen fixation. Some are utilised in industrial processes as well, such as fermentation and bioremediation.

Q4. What are Archaebacteria extremophiles?

Extremophiles are Archaebacteria that thrive in harsh settings such as hot springs (thermophiles), salty surroundings (halophiles), and acidic environments (acidophiles). These organisms have evolved to survive in environments that would be toxic to most other life forms.

Q5. Can Archaebacteria cause human disease?

Archaebacteria aren’t known to trigger human disease in general. They are not related to common infectious disorders, unlike certain Eubacteria. They are instead more commonly found in severe conditions or specific ecological niches.

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