Re: Shuttle lift-off questions

"Randy Poe" <poespam-trap@xxxxxxxxx> wrote:


mmeron@xxxxxxxxxxxxxxxxxx wrote:
In article <e8lb1h$8qk_001@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>, jmfbahciv@xxxxxxx writes:
Does this have anything to do with Ken's comment about
biology is all about surfaces? I'm still thinking about that one.

This one is more complex. But, in a nut shell, biology is about
structures in liquid. and stuff is happening on the surfaces of the
structures. But it could've been a different liquid than water.

Frostbite wouldn't be nearly as much of a problem if
we weren't water based. The problem is that when cells
freeze, they burst their membranes and die. What if freezing
was non-destructive, and things could just thaw back out
again?

Freezing injury is almost completely due to high salt concentrations
that result when the ice crystal excludes dissolved solutes into the
remaining unfrozen fraction. Since solute exclusion is a general
phenomenon associated with crystallization, I don't think we can
attribute frostbite to the anomalous properties of water. Freezing
damage is pretty much all due to dessication.

There are organisms which can survive freezing and thawing.
They must use some such strategy. Viruses don't have any
water. But bacteria do... how do they survive? Or do they?

Most bacteria can survive some types of freezing and thawing without
any particular strategy (other than a cell wall, perhaps). Larger
organisms need to do things like prevent ice crystal nucleation,
inhibit ice crystal growth, buffer the high salt concentrations,
stabilize membranes against dessication, and other strategies.

Ken Muldrew
kmuldrezw@xxxxxxxxxxxx
(remove all letters after y in the alphabet)
.

Relevant Pages

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  • Re: Shuttle lift-off questions
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