Do Archaea Have A Cell Wall: 9 Interesting Facts

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In this article, we came to know about the facts related to archaebacteria and came to know about do archaea have a cell wall or not.

Archaea have cell wall present outside the cell membrane that help to communicate with the outside environment. It is semi-rigid in nature. it helps to protect the cell from external environment.

The cell wall of archaea is made up of pseudopeptidoglycan, this similar to peptidoglycan in morphology but composed of different type of sugars in the polysaccharide chains. Bacterial cell wall made up of peptidoglycan.

Do all archaea have cell walls?

Most of the archaea have cell wall except few like thermoplasma and ferroplasma. The cell wall of Achaea is made up surface-layer protein that further to form S-layer. The cell wall provides both chemical and physical protection.

Methanobacteria have cell wall made up of pseudopeptidoglycan. Pseudopeptidoglycan is chemically different from eukaryotic peptidoglycan as it lacks D-amino acids and N-acetylmuramic acid.

Other cell wall structure which are observed in archaea are pseudomurein, methanochondroitin, glutaminyl glycan, sulfated heteropolysaccharides and protein sheaths. They are sometimes associated with other type of proteins like STABLE proteases or the bindosome.

220px Halobacteria
Halobacteria from Wikipedia

Why do archaea have cell wall?

Archaea is the single-cell organisms which have cell-wall outside the cytoplasmic membrane. The cell wall protects against the mechanical and osmotic stress. Cell wall also help to develop the turgor pressure.

Turgor pressure is the pressure applied by the cell against the cell wall. In the drought, plant cell wall helps to maintain the structural integrity of its cell shape of different plant parts like stem, leaves and other structure.

Cell wall of archaea is main connecting link of cell to the external environment. It will help to maintain internal constituents of cell.

What is unique about the cell wall on archaea?

Cell wall of archea constituted by unusual lipids having reapeating units of isoprenyl grouped joined to the glycerol molecule and glycoprotein S-layer formed lattice like arrangements taht attached to the membrane.

Archaea lack normal peptidoglycan which is usually common in prokaryotes cells. In the methanogen archaea, pseudomurein layer (similar to peptidoglycan structure).

Archaea produced various type of different type of glycan-binding proteins. This glycan is responsible for bacterial colonization. Glycoprotein produced by archaea responsible for many types of linkages.

Archaea call wall composition

The archaea cell wall ids formed by a protein surface S-layer. This S-layer proteins have ability to form 2-dimensional crystals, which have a square (p4), oblique (p2) or hexagonal (p3 or p6) symmetry.

Archaeal S-layer proteins are modified itself by attaching of N-linked and in some of cases, by attaching O- linked glycans.

Archaea which lack S-layer have a second outermost membrane or sugar polymer like heteropolysaccharides, pseudomurein, methanochondroitin as their cell envelope. These all polymeric call wall can either formed as a sole cell wall structure or be supported by additional S-layer.

Archaea cell wall diagram

do archaea have a cell wall
Membrane structures of archea from Wikipedia Top, an archaeal phospholipid: 1, isoprene chains; 2, ether linkages; 3, L-glycerol moiety; 4, phosphate group. Middle, a bacterial or eukaryotic phospholipid: 5, fatty acid chains; 6, ester linkages; 7, D-glycerol moiety; 8, phosphate group. Bottom: 9, lipid bilayer of bacteria and eukaryotes; 10, lipid monolayer of some archaea.

Are archaea cell wall rigid?

Archaea cell wall composed of different kind of polysaccharides and glycoconjugates. The cell wall of archaea is devoid of peptidoglycan still it possesses rigidity that help resistance to the internal osmotic pressure.

The cell wall of archaea is tough, semi-rigid and flexible that protect the cell from external stress. It will provide both structural support and protection. The cell wall of archaea acts as a filtering mechanism.

Is archaea cell wall permeable?

In some Archaea cell wall is semi-permeable in nature. The cell wall is placed outside of cell membrane and allow some of the solute to pass through it and maintain the composition of the cell.

Do archaea cells have a chloroplast?

Like the prokaryotes, archaebacteria have no membrane bound organelles. Membrane bound organelles like nuclei, mitochondria, endoplasmic reticulum, lysosomes, Golgi complexes or chloroplasts are not present in the archaea.

Chloroplast is the organelle that are responsible for the process of photosynthesis. But the archaea bacteria do not perform such kind pf functions. It depends on the other organelles for its nutrition and movement.

Chloroplast is possessed by the high class cells like eukaryotic cells mainly multicellular cells.

Mode of reproduction of archaea

Archaea reproduce asexually by the fragmentation, binary fission, or budding. As archaea is devoid of nuclei so there will be no other reproduction mode observed. There is no species of archaea which form endospores just like prokaryotes.

Archaea habitat

The first one archaeon found in the extremophile (living in highly extreme environments such as hot springs and salt lakes).Their unique cell wall composition help them live them in such harsh environments. no other organisms are able to survive in that extreme conditions.

Archaea are present in almost all kind of habitats including soil, ocean and marshlands. They are present in numerous quantities in oceans.

They are present in human microbiome. They are important and play a necessary role in gut, mouth and on the skin.

Ecological importance of archaea

Archaea play a major role in the most of the biological processes like carbon fixation, nitrogen cycling, organic compound turnover and maintaining microbial symbiotic (beneficial for both organisms) and syntrophic communities.

Nutritional types of archaeal metabolism

  • Phototrophs– there source of energy is sunlight and carbon source is organic compounds. E.g. Halobacterium.
  • Lithotrophs– source of energy is inorganic compounds and carbon sources are organic compounds or carbon fixation. E.g. Ferroglobus, Methanobacteria or Pyrilobus.
  • Organotrophs– source of energy is organic compounds. The organic compounds or carbon fixations are the source of carbon to the archara which are organotrophs. E.g. Pyrococcus, Sulfolobus or Methanosarcinales.

Conclusion

To wrap the article, we state that archaea cell wall is different from the prokaryotes due to presence of pseudomurein, pseudopeptidoglycan and different type of polysaccharide composition. Due to these different types of cell wall composition, it was able to grow and survive in highly extreme environment.

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