Practice question

Archaea differ from Bacteria primarily in membrane biochemistry containing isoprenoid chains ether-linked to glycerol-1-phosphate backbone forming diether archaeol or tetraether caldarchaeol monolayers, contrasting ester-linked fatty acids to glycerol-3-phosphate in Bacteria and Eukarya. Ether linkages confer thermal stability, proton impermeability, and resistance supporting extremophilic lifestyles in hot springs and acidic environments. Additional distinguishing features include absence of typical peptidoglycan, presence of pseudomurein or protein S-layer, unique RNA polymerase complexity, and histone-mediated DNA packaging. These molecular signatures underpin domain separation despite morphological similarity to bacteria.