How are Archaea Different from Bacteria?
Members of Archaea (say ARE-key-uh) differ from bacteria in that they do not have the polymer peptidoglycan as part of their cell wall structure. This tough organic molecule is found in nearly all bacterial cells walls, and is important in the differentiation between Gram-positive and Gram-negative bacteria. In addition to lacking peptidoglycan, Archaeans have unique rRNA sequences. rRNA is the nucleic acid that is a key structural component of ribosomes, organelles that function as the cell’s protein-making machinery. A medically important distinguishing feature of Archaea is that they are not known to cause disease in human or animals. Since this group of organisms was found to have unique rRNA sequences, and to lack peptidoglycan, they are categorized in their own domain. The three domains, or most basic taxonomic groupings of living things, include: • Eubacteria – Single-celled prokaryotic organisms that have peptidoglycan as part of their cell wall structure. • Archaea – Single-ce
