Prblem sets 1-2-3 with answers

Prblem sets 1-2-3 - 1 Rank these 3 phospholipids in order from most fluid(1 to least fluid(3 and explain your reasoning a palmitate(C16 saturated

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1) Rank these 3 phospholipids in order from most fluid (1) to least fluid (3), and explain your reasoning? a- palmitate (C16, saturated) is (2), because it has no double bonds and has van der Waals contacts (from the saturated carbons) that give rigidity to the membrane. b- stearate (C18, saturated) is (3), because it has no double bonds and has the highest number of carbons making the bilayer very rigid and viscous . c- Oleate (C18, unsaturated) is (1), because double bonds introduce kinks to the structure preventing crystallization and tight packaging. 2) How are the structures of transmembrane proteins different form the structures of porins? Which analysis of topology is used to illustrate such differences? Transmembrane proteins have many hydrophobic patches within polar residues. Those hydrophpobic domains could be the N-terminal signal peptide, the membrane anchor domains and the stop transfer domains. However porins fold as Beta barrels and do not have hydrophobic domains. They interact with the membrane via alternating hydrophilic and hydrophobic residues in their B-sheets Such differences in the amino acid sequences that dictate the topology of proteins are illustarted by a technique called “hydropathy analysis”. 3) When reconstituting a carrier (that uses the Na gradient to export Ca to the cell
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This note was uploaded on 04/02/2008 for the course MCB 130 taught by Professor Schekman during the Spring '08 term at University of California, Berkeley.

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Prblem sets 1-2-3 - 1 Rank these 3 phospholipids in order from most fluid(1 to least fluid(3 and explain your reasoning a palmitate(C16 saturated

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