Question

In light of the recent classification of living organisms into three domains of life (bacteria, archaea and eukarya), which of the following statements is true about archaea?
A) Archaea completely differs from both prokaryotes and eukaryotes
B) Archaea completely differ from prokaryotes
C) Archaea resemble eukarya in all respects
D) Archaea have some novel features that are absent in other prokaryotes and eukaryotes

Answer 1

Hint: Archaea are single-celled species that make up the earth's third domain of life. As a result, they're distinct from the other two domains, Bacteria and Eukaryotic organisms. They can be found in several habitats such as lakes, soil and even in the Dead Sea due to their ability to withstand harsh conditions.

Complete answer:
The Archaea are characterised by the following characteristics:
a. Prokaryotic cells are archaea.
b. Unlike Bacteria and Eukaryotes, Archaea have membranes made up of branched hydrocarbon chains (many of which have rings inside them) bound to glycerol by ether linkages.
c. Archaea has no peptidoglycan in its cell walls.
d. Some antibiotics that affect bacteria are ineffective against Archaea, but some antibiotics that affect Eukarya are effective.
e. Archaea have their own rRNA, as shown by the existence of molecular regions that are distinct from those found in Bacteria and Eukarya.

Archaea have some characteristics of bacteria, some characteristics of eukaryotes, and some characteristics that are peculiar to them, which is consistent with their classification as a third type of life. They also have a wide variety of biological properties, and all of them have evolved to withstand harsh environmental conditions. In terms of size, complexity, and organisation, archaeal genomes are similar to bacterial genomes, and they show signs of being formed by similar processes, such as lateral gene transfer and transposable genetic element behaviour.


Thus from the above discussion, it is clear that the correct answer is option ‘D’ - Archaea have some novel features that are absent in other prokaryotes and eukaryotes.

Note: C. R. Woese and colleagues used small ribosomal RNA (rRNA) sequence comparisons to identify Archaea as a cohesive group in the tree of life in 1977. All organisms have archaea in their microbiota. They play a significant role in the human microbiome in the gut, mouth, and skin. Archaea species are further divided into two phyla that are Euryarchaeota and Crenarchaeota.