BIL 255 Lecture Notes - Lecture 11: Conformational Change, Biological Membrane, Platelet-Derived Growth Factor
26 Apr 2018
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Document Summary
Barrier, selective, transduce info, mechanically elastic, eukaryotic compartments, variable composition, bilayer. Membranes form many diff. compartments: plasma membrane = single bilayer membrane that encloses the cell, exoplasmic face = facing exterior, cytosolic face = facing cytosol, two membranes separated by small intermembrane space, nucleus, mitochondria, chloroplast. Synthesis of fatty acids: growing fatty acid chain linked to coenzyme a, sequential addition of two acetyl units at a time, additional enzymes form double bonds. Other membrane lipids: cholesterol (sterol, galactocerebroside (glycolipid) Phospholipids spontaneously form bilayers: close in on themselves to form sealed compartments, energetically favorable stable, avoids the exposure of the hydrophobic tails to water. Fluidity of membrane depends on its composition: the closer and more regular packaging of tails, the more viscous (less fluid) the membrane is, # of hydrocarbons, # of double bonds, cholesterol (stiffens membrane) Glycolipids: sugars constituent of the plasma membrane & participate in cell signaling found exclusivelt in noncytosolic monolayer distributed almost equally in both monolayers.
