This document compares and contrasts eubacteria, archaebacteria, and eukaryotes. Eubacteria are unicellular prokaryotes that have cell walls containing peptidoglycan. Archaebacteria are also unicellular prokaryotes but they do not have cell walls containing peptidoglycan. Eukaryotic cells are multicellular and contain membrane-bound organelles like the nucleus. They reproduce sexually in most cases. Chemotaxonomy uses biochemical similarities and differences to characterize and classify bacteria, providing important information for identification that complements phylogenetic analysis. Key chemotaxonomic markers include cell wall composition, lipids, proteins, and other complex molecules.

1. DIFFERENCE
BETWEEN
EUBACTERIA,
ARCHAEBACTERIA
AND EUKARYOTES

2. EUBACTERIA
• Eubacteria are unicellular prokaryotic organisms, also known as true bacteria.
• All types of bacteria are included (Gram’s positive and negative) under the eubacteria except for
Archaebacteria.
• Eubacteria lack a membrane-bound nucleus.
• The cell wall is made up of peptidoglycan (murein) in a cross-linked chain pattern
• The plasma membrane contains cytosol (fluid), which is primarily composed of water (80%), but it has a
gel-like consistency due to the presence of dissolved nutrients, DNA, cytoskeletal elements DNA, and other
substances.
• Their cells consist of lipids, carbohydrates, protein, and nucleic acid.
• A chromosome is single and circular, but some bacteria have two chromosomes (like vibrio cholera), while
other species have a linear chromosome, and nucleosomes may be present.
• They have flagella, which helps in locomotion. Some of the eubacteria have pili.
• Most of the eubacteria are heterotrophic.
• Eubacteria reproduce by binary fission or by budding.

4. ARCHAEBACTERI
A
• Archaebacteria are unicellular prokaryotes and belong to the kingdom archaea.
• They don’t possess the membrane-bound organelles. They don’t have nuclei, endoplasmic
reticulum, Golgi complexes, mitochondria, chloroplasts, or lysosomes.
• Their cell wall doesn’t contain peptidoglycan. The rigid cell wall supports the cell and allows an
archaebacterium to maintain its shape as they are composed of Pseudomurein, which prevents
archaebacteria from the effects of Lysozyme.
• Archaebacteria have lipids in their cell membranes. They are composed of branched hydrocarbon
chains, connected to glycerol by ether linkages.
• Since these organisms don’t have nuclei, the genetic material floats freely in the cytoplasm.
• Their DNA contains a single, circular molecule, which is compact and tightly wound. No protein is
associated with DNA.
• The archaebacterial cell may contain plasmids, which are small, circular pieces of DNA.
• Archaebacteria are a special kind of bacteria because they survive in some of the harshest habitats.
• Archaebacteria reproduce by an asexual process known as binary fission.

5. EUKARYOTE
S
• Eukaryotic cells are multicellular (they have a true nucleus and membrane-bound organelles).
• The cell organelles and nucleus are embedded in the cytoplasm. The cell is covered with the
plasma membrane.
• The genetic material of the cell is present in the nucleus that is also membrane-bound. The
DNA of the cell is arranged in the form of thread-like structures called chromosomes
• The nuclear membrane is continuous with the endoplasmic reticulum. Mitochondria are
called the powerhouse of the cell as it synthesizes energy-rich molecule ATP. The
endoplasmic reticulum (ER) carries out modification of proteins and synthesis of lipids.
There is two type of ER, namely rough ER and smooth ER. Rough ER has ribosomes on its
membrane. Golgi apparatus carries out sorting, tagging, packaging, and distribution of
lipids and proteins. Peroxisomes carry out oxidation reactions that break down fatty acids
and amino acids. Vesicles and vacuoles are storage organelles. Apart from these organelles,
the animal cell contains lysosomes and centrosomes.
• Sexual reproduction is seen in almost all of the eukaryotes but in some single-celled
eukaryotes like yeast cells, reproduces asexually via mitosis or fission

7. DIFFERENCE BETWEEN EUBACTERIA, ARCHAEBACTERIA AND EUKARYOTES

13. CHEMOTAXONOMY AND ITS MARKERS
• Chemotaxonomy is defined as the complete characterization made using the similarities and
differences of the biochemical properties of bacteria.
• Chemotaxonomy examines the distribution of biological and chemical macromolecules
containing; amino acids, peptides, lipids, polysaccharides and other related polymers, proteins,
enzymes as well as, other complex polymeric molecules such as isoprenoid quinone and sterol
among members of different taxa. Then, it uses this information for classification and
identification.
• Phylogenetic data give a hierarchical skeleton of the relationship between bacteria but, it does
not always provide reliable information when describing taxa of bacteria above the species level.
• Chemotaxonomic procedures are applied to determine the most important differences between
species and strains comparatively in the direction of polyphasic studies. These procedures
illustrate the separation of biochemical structures of the microorganisms thus, the properties of
each species are explained using such analysis.

14. • In general, the characters used in bacterial chemotaxonomy are; peptidoglycan, Diamino acids,
polysaccharides, teichoic acids, mycolic acid, fatty acids, polar acids, isoprenoid quinones, polyamines,
prokaryotic pigments and LPS.
• Chemotaxonomy provides an important solution for the identification of bacterial species so
chemotaxonomic analysis should be mandatory to identify new species. In the past, when chemotaxonomic
classification was not yet to be fully understood, many species were classified and published.
• The species classified during this period have to be reclassified and identified as they might belong to
different groups. A striking example is that most of the bacteria belonged to the genus Thermomonospora and
Microtetraspora at the beginning of 1998, were later identified as members of the genus Nonomuraea and were
reclassified with the help of chemotaxonomic analysis . No matter how much the chemical structure of the
bacteria is present in their genetic architecture, the structure may be affected by the feeding site, osmotic
pressure, pH, etc. as well as other environmental conditions. A standardized developmental procedure should
be applied for the development of cultures, prior to a comparative chemotaxonomic study. Standardized
culture conditions are of great importance in studies involving the qualitative analysis of chemical data [23].
As a result; in addition to molecular analyses and numerical studies, chemotaxonomic markers are important
in the biochemical structure of living bacterial organisms so in their identification