What is the freeze-fracture technique and why is it useful in cell biology?
Freeze fracture is unique among electron microscopic techniques in providing planar views of the internal organization of membranes. Deep etching of ultrarapidly frozen samples permits visualization of the surface structure of cells and their components.
How can freeze fracture be used to determine the orientation of a protein in a membrane?
How can freeze-fracture be used to determine the orientation of a protein in a membrane? Freeze-fracture allows a cell to be cleaved in between the lipid bilayer, splitting the plasma membrane into two layers. Cells routinely form from non-living materials.
Which is the best definition of freeze fracture?
Definition of freeze fracture. 1 or less commonly freeze-fracturing ˈfrēz-ˌfrak-chə-riŋ , -shə- : preparation of a specimen (as of biological tissue) for electron microscopic examination by rapid freezing, fracturing along natural structural lines, and preparing a replica of the exposed structural details…
How is freeze fracture used in electron microscopy?
Freeze-fracture electron microscopy The freeze-fracture technique consists of physically breaking apart (fracturing) a frozen biological sample; structural detail exposed by the fracture plane is then visualized by vacuum-deposition of platinum-carbon to make a replica for examination in the transmission electron microscope. The four …
What is the difference between freeze fracture and freeze etching?
Freeze fracture describes the technique of breaking a frozen specimen to reveal internal structures. Freeze etching is the sublimation of surface ice under vacuum to reveal details of the fractured face that were originally hidden.
How is a freeze fracture made into a replica?
The fractured membrane is covered with a fine layer of platinum by a process known as shadowing to make the replica. The topographical features of the fractured membrane are then converted into variations in thickness of the deposited platinum layer of the replica (Bullivant & Ames, 1966 ).