Compare Archaebacteria, Bacteria and Eukaryotes: Similarities and Differences (Table)

Archaebacteria vs Bacteria vs Eukarya

The Three Domain System of Classification by Carl Woese (1977) based on variations in 16S rRNA sequence, divided the entire living organism in the biosphere into three major groups called Domains namely Archaea Bacteria and Eukarya or Eukaryota.

In the earlier systems of classifications, Archaea were treated as a unique type of bacteria called Archaebacteria and they were included in the Kingdom Monera along with true bacteria and Cyanobacteria (blue green algae).  Now we are certain that Archaea possess distinct difference from true bacteria in their cellular structures and metabolic activities, and also they have a unique and separate evolutionary ancestry.

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Archaea shows some characters similar to true bacteria where as some unique sets of characters they share between eukaryotes. Due to these peculiarities, the group Archaea is now recognized as a distinct domain of life.

The present post article describe what all are the similarities and difference between Archaea, Bacteria (eubacteria) and Eukarya (eukaryote) with a comparison table for easy understanding.

Archaea Bacteria and Eukarya

Similarities and Differences Between Bacteria, Archaebacteria and Eukaryotes: Comparison Table

Sl. No.FeaturesBacteria (Eubacteria)Archaea (Archaebacteria)Eukarya (Eukaryotes)
1Cell sizeUsually 0.5 – 4 µUsually 0.5 - 4µGreater than 5 µ
2Membrane-enclosed nucleus with nucleolusAbsentAbsentPresent
3Complex internal membrane bounded organellesAbsentAbsentPresent
4Cell wallIf present, almost always have peptidoglycan containing muramic acidVariety of types, no muramic acid in the cell wallNo muramic acid, cellulosic if present (in plants)
5Membrane LipidHave ester linked, straight chained fatty acidsHave ether linked branched aliphatic chainsHave ester linked, straight chained fatty acids
6Gas vesiclesPresentPresentAbsent
7Transfer RNAThymine present in most tRNAsNo thymine in T or TψC arm of tRNAThymine present
8Formylation of Methionine (first amino acid in protein synthesis)Methionine formylatedMethionine not formylatedMethionine not formylated
9Polycistronic mRNAPresentPresentAbsent
10Introns in mRNAAbsentAbsentPresent
11Introns in tRNAAbsentPresentPresent
12Post transcriptional modifications of RNA (mRNA Splicing, capping, and poly A tailing)AbsentAbsentPresent
13Ribosome size70S70S80S
14Elongation factor 2 (EF2)Does not react with diphtheria toxinReacts with diphtheria toxinReacts with diphtheria toxin
15Sensitivity to chloramphenicol and KanamycinSensitiveInsensitiveInsensitive
16Sensitivity to anisomycinInsensitiveSensitiveSensitive
17RNA polymerase enzyme typesOne typeSeveral typesThree types (RNA Pol I, II, III)
18Structure of RNA PolymeraseSimple, 4 subunitsComplex, 8-12 subunitsComplex, 12-14 subunits
19Rifampicin sensitivity of RNA polymeraseSensitiveInsensitiveInsensitive
20Chromosomes and Replication of genetic materialCovalently closed circular DNA with unique replication systemCovalently closed circular DNA with replication system more or less similar to eukaryotesLinear chromosomes with unique replication system different from bacteria
23Polymerase II type promotersAbsentPresentPresent
24Similar ATPaseNoYesYes
26Nitrogen fixationPresentPresentAbsent
27Chlorophyll based photosynthesisPresent in some formsAbsentPresent in plants
29MulticellularityAbsentAbsentUsually Present
30Growth at temperature above 80oCSome can growMost of them can growNone of them can grow

Key questions:

What are the difference between Archaea (Archaebacteria) and Bacteria (Eubacteria)?
What are the difference between Archaea (Archaebacteria) and Eukarya (Eukaryotes)?
How Archaea is different from Bacteria?
How Archaea is similar to Eukaryotes?
How to compare Archaea with bacteria and eukaryotes?

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