BIO-1 Lecture Notes - Lecture 3: Membrane Protein, Photobleaching, Cholesterol
Document Summary
General properties of membranes (shared by all membranes) Phospholipids move laterally in membranes very rapidly. On average a phospholipid will change places with an adjacent phospholipid. Lateral movement of phospholipid molecules within the membrane leaflet is the. Fluidity is possible because the phospholipids are not linked to each other by. Movement from one leaflet to another is hard (flipping) requires high energy and. Frap molecule and is a consequence of thermal agitation of the molecules covalent bonds but by weak non-covalent interactions basis of membrane fluidity isn"t favorable. Fluorescence restoration after photobleaching used to measure membrane fluidity. 2) irradiate with strong laser beam that destroys fluorochromes in irradiated area. 3) monitor fluorescence intensity in the irradiated area over time and observe what happens. After irradiation there is very low level of fluorescence, then molecules carrying undamaged fluorochrome diffuse into the irradiated area, bringing about the recovery of fluorescence. Low temperature membrane bilayers freeze (crystalline-like state) = low fluidity.
