Archaea and Bacteria are both single-celled organisms, but they belong to separate domains due to significant differences in their genetic makeup, biochemistry, and cellular structures.
- Genetic Differences: Archaea and Bacteria have distinct ribosomal RNA (rRNA) sequences. Archaea’s genetic code is closer to that of eukaryotes (complex organisms), while Bacteria have their own unique traits.
- Cell Wall Composition: Bacteria have cell walls made of peptidoglycan, whereas Archaea use pseudopeptidoglycan or other unique substances, highlighting a key structural difference.
- Metabolism and Habitat: Archaea can thrive in extreme environments (hot springs, deep-sea vents), thanks to unique enzymes and metabolic pathways, such as methane production (methanogenesis), which Bacteria do not possess.
- Ribosomes: Archaea’s ribosomes are more similar to eukaryotes than Bacteria, further indicating their closer evolutionary relationship to complex organisms.
These differences in genetics, cell structure, and metabolism explain why Archaea and Bacteria are classified into different domains, even though both are prokaryotic organisms.
