All organisms are made up of cells which is the basic unit of life. Some are composed of single cells while others are composed of multiple cells. Archaea and Bacteria are two major single-celled or unicellular organisms categorised as Prokaryotes that is they do not have a well-defined nucleus and are lacking membrane-bound organelles. Even though both of them are Prokaryotes, they have a lot of differences.
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Main Differences Between Archaea and Bacteria
- Both Archaea and Bacteria are single-celled prokaryotes. But Archaea shows certain characteristics of Eukaryotes as well. Like Eukaryotes, they have three RNA. But bacteria contain only one Ribonucleic Acid (RNA).
- Archaea can exist in extreme and unusual conditions like salty water, hot springs, deeper regions of oceans, marshes and gastrointestinal tract of human beings. Bacteria, on the other hand, are almost omnipresent. They are found in water, soil, radioactive wastes and multicellular animals and so on.
- Both Archaea and Bacteria procreate asexually but their mechanisms are different. Archaea procreate by the mechanisms of budding, binary fission and fragmentation. Bacteria, on the other hand, procreate by producing spores so that they can remain latent for many years in all conditions.
- The cell wall of Archaea is not made up of peptidoglycan. It is made up of simpler connecting subunits called the S-layer or pseudopeptidoglycan. The cell wall of Bacteria, on the other hand, is composed of peptidoglycan accompanied by lipopolysaccharide.
- The plasma membrane of Archaea has lipids covered with hydrocarbons which are sometimes branched and form monolayers. These lipids have ether bonds that connect the glycerol backbones. While, the plasma membrane of Bacteria contains lipids having ester bonds and enclosed with fatty acids.
Conclusion
Archaea, Bacteria and Eukaryotes constitute three major domains of life. All living things are categorised into these domains based on their structural, genetic and biochemical features. Among these, Archaea and Bacteria are single-celled organisms. But they have considerable differences in terms of their genetic, physical and physiological features which is enough to categorise them into two separate domains of life.
However, it is interesting to note that this separation between Archaea and Bacteria is very recent. Earlier they constituted a single domain which was known as the Archaebacteria kingdom.
References
- https://www.nature.com/articles/nature08465
- https://academic.oup.com/femsec/article-abstract/39/1/1/535284