BSCI 330 Lecture Notes - Lecture 3: Beta Barrel, Alpha Helix, Photobleaching
5 Oct 2017
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Document Summary
Structural details of biomembranes cannot be resolved with light. Images created of the plasma membrane are due to staining. More sensitive methods are needed to look at the plasma membrane. Membranes of cell and organelles look very similar, suggest a similar architecture. Danielli and dawson proposed that the cell membrane is made up of a lipid layer sandwiched between two layers of proteins. Observed a dark-light-dark pattern of staining, suggesting a bilayer. Fixed tissue is fixed onto a plastic block. Fixation of tissue involves reacting with oxidizing agents (kmno4, oso4) Diamond blade cuts block into thin slivers. Examined with electron stream and image captured on a fluorescent screen. Composition of various plasma membrane constituents varies among different membranes due to different functions. Created arachidic acid film on a pan of water. Film compressed with a paddle pressure on the paddle measured. Pressure increased as the film was compressed. Took rbc and extracted lipids with acetone.
