low boiling point

Jim Mansfield mansfield at zeno.ibd.nrc.ca
Fri Mar 24 12:38:34 EST 1995


In article <Pine.A32.3.91.950323150650.72973A-100000 at academ01.mty.itesm.mx> dsleal at ACADEM01.MTY.ITESM.MX ("M.C. Diana Sara Leal Klevezas") writes:
>
>If I'm wrong regarding the pressure building up in warm tubes, the 
>possibilities are even more exciting, here is the idea: The water boils 
>because the molecules get excited enough to do so. If less energy is 
>needed to boil the water, less energy might be needed to break the 
>hidrogen bonds between DNA strands, which means that under those 
>circumstances, one might need lower temperatures to reach DNA melting 
>point. If this is true, the consecuences are that your Taq will last 
>loger!!!. 

Thankfully, hydrogen bonding and similar prcesses are not affected by
pressure changes of the magnitute we are discussing - otherwise life
as we know it would not be possible in Peru at all! The reason less
energy and, hence lower temperatures, are needed at high altitudes is
the vapour pressure of the liquid does not need to be as high before
it matches atmospheric pressure. As the temp. of a liquid rises, so 
does its vapour pressure. Once it reaches atmospheric pressure, voila,
boiling. Putting a lid on the vesselwill raise the pressure of the gas
over the liquid, raising its boiling point.

-Jim

-- 
---------------------------------------------------------------------
Jim Mansfield                          internet: mansfield at ibd.nrc.ca
Institute for Biodiagnostics, NRCC     phone:    (204) 984-5191
http://www.ibd.nrc.ca/~mansfield/      fax:      (204) 984-5472



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