What does the term "The Lipid Divide" refer to?
The Lipid Divide refers to the difference in membrane lipids between Bacteria and Archaea on one hand and Eukarya on the other hand (option b).
Membrane Lipid Composition
The Lipid Divide refers to the distinction in membrane lipid composition between Bacteria and Archaea compared to Eukarya. Bacteria and Archaea both possess membrane lipids called phospholipids, which consist of a glycerol backbone and fatty acid chains. However, there is a significant difference in the chemical structure of the fatty acid chains.
Difference in Lipid Structure:
Bacteria and Eukarya typically have fatty acids linked to the glycerol backbone by ester bonds, resulting in ester lipids. In contrast, Archaea have unique membrane lipids known as ether lipids, where the fatty acids are connected to the glycerol backbone through ether linkages.
Evolutionary Divergence:
This distinction in membrane lipid composition is one of the factors that differentiate Archaea from Bacteria and Eukarya. The Lipid Divide reflects the evolutionary divergence and the distinct adaptations of Archaea in their lipid composition compared to the other domains of life.