Which domain has ether-linked membrane lipids?

Which domain has ether-linked membrane lipids?

• A. Bacteria
• B. Archaea
• C. Eukarya
• D. Fungi

Answer: (B)

Membrane lipid chemistry is a clue to how different life domains are built. In Bacteria and Eukarya, membrane lipids have fatty acids attached to glycerol by ester bonds. In Archaea, the lipid tails are isoprenoid chains attached by ether bonds to glycerol. Ether linkages are more chemically stable under heat and harsh conditions, and archaeal membranes can form either bilayers or the more Forum-like monolayers that help stability in extreme environments. That distinctive ether linkage is why Archaea are the domain known for ether-linked membrane lipids. Fungi, as a part of Eukarya, share ester-linked lipids with other bacteria and eukaryotes, so they don’t have ether-linked membranes.

Membrane lipid chemistry is a clue to how different life domains are built. In Bacteria and Eukarya, membrane lipids have fatty acids attached to glycerol by ester bonds. In Archaea, the lipid tails are isoprenoid chains attached by ether bonds to glycerol. Ether linkages are more chemically stable under heat and harsh conditions, and archaeal membranes can form either bilayers or the more Forum-like monolayers that help stability in extreme environments. That distinctive ether linkage is why Archaea are the domain known for ether-linked membrane lipids. Fungi, as a part of Eukarya, share ester-linked lipids with other bacteria and eukaryotes, so they don’t have ether-linked membranes.