- freeze fracture
Method of specimen preparation for the electron microscope in which rapidly frozen tissue is cracked so as to produce a fracture plane through the specimen. The surface of the fracture plane is then shadowed by heavy metal vapour, strengthened by a carbon film, and the underlying specimen is digested away, leaving a replica that can be picked up on a grid and examined in the transmission electron microscope. The great advantage of the method is that the fracture plane tends to pass along the centre of lipid bilayers, and it is therefore possible to get en face views of membranes that reveal the pattern of integral membrane proteins. The E-face is the outer lamella of the plasma membrane viewed as if from within the cell, the P-face the inner lamella viewed from outside the cell. Fracture planes also often pass along lines of weakness such as the interface between cytoplasm and membrane, so that outer and inner membrane surfaces can be viewed. Further information about the structure can be revealed by freeze etching. Extremely rapid freezing followed by deep etching has allowed the structure of the cytoplasm to be studied without the artefacts that might be introduced by fixation.
Dictionary of molecular biology. 2004.
Look at other dictionaries:
freeze fracture — also freeze fracturing n FREEZE ETCHING freeze fracture vt * * * see freeze fracturing … Medical dictionary
freeze-fracture — ˈ ̷ ̷ ˌ ̷ ̷ ̷ ̷ noun also freeze fracturing : freeze etching herein • freeze fracture ˈ ̷ ̷ ¦ ̷ ̷ ̷ ̷ transitive verb * * * /freez frak cheuhr/, v.t., freeze fractured, freeze fracturing. to prepare ( … Useful english dictionary
freeze fracture — noun Date: 1973 preparation of a specimen (as of tissue) for examination by an electron microscope after freezing, fracturing along natural structural lines, and preparing a replica (as by simultaneous vapor deposition of carbon and platinum) •… … New Collegiate Dictionary
freeze-fracture — adjective see freeze fracture … New Collegiate Dictionary
freeze-fracture — /freez frak cheuhr/, v.t., freeze fractured, freeze fracturing. to prepare (material) for the electron microscope by freeze fracturing. [1965 70] * * * … Universalium
freeze-etching — noun Date: 1968 freeze fracture … New Collegiate Dictionary
freeze cleavage — See freeze fracture … Dictionary of molecular biology
freeze-fracturing — noun see freeze fracture … Useful english dictionary
fracture — 1. To break. 2. A break, especially the breaking of a bone or cartilage. [L. fractura, a break] apophysial f. separation of apophysis from bone. articular f. a f. involving the joint … Medical dictionary
freeze-thaw weathering — a process of physical or mechanical weathering. In areas which experience a diurnal temperature range above and below 0蚓 then water is frozen and thawed on a daily basis. As it expands when freezing, it can widen cracks in which it is held… … Geography glossary