1. The three domains of life do not all have the same membrane phospholipids. Me
ID: 42203 • Letter: 1
Question
1. The three domains of life do not all have the same membrane phospholipids. Membrane lipids have an essential role in adaptation of organisms to their environment. The branched phospholipid chains seen in Domain Archaea can cross-link th other phospholipids from opposite sides of the bilayer membrane, providing membrane structural integrity. With that in mind, chose the best answer from the following question. Post your answer on the discussion board and then explain why you chose the answer that you did. Archacal Membrane Lipids Archaea have different phospholipids in their membranes from either Bacteria or Eukarya. as shown in this figure The Archacal phospholipids a) suggest that Archaea are of extraterrestrIal origin. b) likely arose from adaptation to extreme environments by an ancestral Archaeal cell. C) indicate that Archaea are more primitive than Bacteria and Eukarya.Explanation / Answer
Answer:b
Like arose from adaptation to extreme environments by an ancestral Archaeal cell
The phospholipids of eukarya and Bacteria are fatty acids, chains of usually 16 to 18 carbon atoms. Archaea do not use fatty acids to build their membrane phospholipids. Instead, they have side chains of 20 carbon atoms built from isoprene.
The side chains of achaeal membranes built from different components, but the chains themselves have a different physical structure. Because isoprene is used to build the side chains, there are side branches off the main chain. The fatty acids of bacteria and eukaryotes do note have these side branches, and this creates some interesting properties in archaeal membranes.
The side branches has ability to form carbon rings. This happens when one of the side branches curls around and bonds with another atom down the chain to make a ring of five carbon atoms. Such rings are thought to provide structural stability to the membrane, since they seem to be more common among species that live at high temperatures.
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