Meaning of Archaea
What is Archaea:
It is known as archaea or archaea to a diversity of unicellular microorganisms that make up the archaea kingdom and have their own domain apart from that of eukaryotes and bacteria, although they are similar to the latter.
Archaea are characterized by having a prokaryotic-type morphological structure, that is, they do not have a specific nucleus, and are organisms capable of developing under extreme conditions.
Its name derives from the Greek αρχαία (arkhaia), which means 'the old ones', given that up to now it has been one of the oldest molecular structures that has been studied and that it is conserved with few modifications, compared to other microorganisms whose structures have varied much more throughout the weather.
It is worth mentioning that the first classification of the archaea as a kingdom of microorganisms was carried out in 1977 by Carl Woese and George E. Fox, since they were previously considered prokaryotic bacteria.
Characteristics of archaea
The main characteristics of archaea are the following:
- They have a unicellular membrane composed of lipids that allow them to have greater thermal resistance.
- The cell wall is made up of proteins that form an S-layer that protects the outside of the cell.
- They have flagella similar to bacteria, only these can be longer and thicker.
- Its reproduction is asexual.
- These molecules measure between 0.1 μm and 15 μm.
- Part of their energy is taken from sunlight, organic compounds or hydrogen.
- Some molecules have sizes and shapes very similar to bacteria, and others have very particular shapes, such as square, elongated or flat.
- These microorganisms can be found in various habitats on the planet.
- They are resistant and can easily develop in extreme environments, that is, at high temperatures, high concentrations of salinity, on the seabed, in swamps, oil wells or in the intestines of humans and even ruminants.
Classification of archaea
The classifications established to determine the domains of archaea are based on the phylogenetic condition and on the study of ribosomal RNA sequences, hence five main groups have been established, which are:
- Euryarchaeota: it is one of the most studied groups and is based on the rRNA sequence.
- Crenarchaeota: also known as eocytes, they withstand extreme temperatures and a large amount is found in the oceans.
- Korarchaeota - This group has hydrothermal qualities and they are not abundant.
- Nanoarcheaota: it was discovered in 2002 and survives in extreme conditions.
- Thaumarchaeota: it was discovered in 2008 and participates in the nitrogen and carbon cycles.