BC368 Biochemistry of the Cell II. Biological Membranes Chapter 11: Part 1 February 11, 2014. Plasma Membrane.
Chapter 11: Part 1
February 11, 2014
“Possibly the decisive step [in the origin of life] was the formation of the first cell, in which chain molecules were enclosed by a semi-permeable membrane which kept them together but let their food in.”
J. B. S. Haldane, 1954
Membrane is composed of:
linkageMembrane Lipids: 1B. Sphingolipids
Deposits of gangliosides in Tay Sachs brain
Multiple Transmembrane Segment Proteins
Beta Barrel Transmembrane Proteins
Domains of gel/fluid lipid segregation in a model membrane vesicle, which is a mixture of fluid dilaurylphosphatidylcholine phospholipids with short, disordered chains and gel dipalmitoylphosphatidylcholine phospholipids with long, ordered chains. A red fluorescent lipid analogue (DiIC18) partitions into the more ordered lipids, whereas a green fluorescent lipid analogue (BODIY PC) partitions into domains of more fluid lipids. These domains in a model membrane are much larger than the domains of cell membranes.