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Tools for studying cells question

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Tools for studying cells question

Postby thewax » Fri Dec 26, 2008 12:00 am

Note: This is not a homework question. This is part of a study effort for a big test coming up soon.

What is freeze fracture? Freeze-etching? Could someone explain this to me?

Progress I made: I have a book that simply mentioned freeze fracture and freeze-etching but doesn't bother to explain it in detail (so that I would understand). My other books that I had did not have it at all, so I went on the web to try to research it. Websites such as this one: http://www.udel.edu/biology/Wags/b617/ffe/ffe7.gif were too complicated for me to understand and assumed that I had some basic knowledge of freeze fracture and freeze etching. So I turned here.
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Postby MrMistery » Fri Dec 26, 2008 6:07 pm

from wikipedia
"Freeze-fracture or freeze-etch – a preparation method particularly useful for examining lipid membranes and their incorporated proteins in "face on" view. The fresh tissue or cell suspension is frozen rapidly (cryofixed), then fractured by simply breaking or by using a microtome while maintained at liquid nitrogen temperature. The cold fractured surface (sometimes "etched" by increasing the temperature to about -100°C for several minutes to let some ice sublime) is then shadowed with evaporated platinum or gold at an average angle of 45° in a high vacuum evaporator. A second coat of carbon, evaporated perpendicular to the average surface plane is often performed to improve stability of the replica coating. The specimen is returned to room temperature and pressure, then the extremely fragile "pre-shadowed" metal replica of the fracture surface is released from the underlying biological material by careful chemical digestion with acids, hypochlorite solution or SDS detergent. The still-floating replica is thoroughly washed from residual chemicals, carefully fished up on EM grids, dried then viewed in the TEM."
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Postby thewax » Sat Dec 27, 2008 5:15 pm

okay... thanks!!!!!!!!!!! :)
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