Why aren’t living cells more tolerant to extreme heat or cold? Is it just because that’s the way God made it?
There are probably more qualified people to answer this question completely, but I can get things started.
As far as cold goes, once ice crystals begin to form, they destroy the structure of the cell. That is the cytoskeleton, the cell membrane, the nucleous, anything. Species that can survive extremely cold situations, do so due to some chemistry in their system that prevents ice from crystalizing.
Heat, I think may be a bit more complicated. I am not a biochemist. As the molecules get hotter, they have more kinetic energy. Protiens will denature (lose their structure, that’s why eggs turn white when cooked), but I would guess that the cell was in deep trouble before then. The cell membrane is basically just a loose assembly of molecules. Give these molecules enough kinetic energy, and I bet they completely disorder.
There is no doubt that life as we know it is a delicate balance.
“God” has nothing to do with it, I guarantee you.
However, your premise is wrong right from the start, anyway. There are organisms which can tolerate extreme heat, called thermophiles some of which can withstand (and thrive in) temperatures of up to 169 C. Many of these organisms can be found living in and around deep-ocean volcanic thermal vents called “black smokers” for the dark, cloudy plumes of superheated water they spew forth.
I’d like to read about this ‘guarantee’. It ought to be good.
I think I did a poor job describing my premise. I know that there are organisms that can withstand extreme temperatures. I’m asking why aren’t all organisms capable of such.
I understand what happens to cell structures under extreme temperatures. Is there a reason why proteins denature at 180 deg F and not 452 deg F?
What holds a protiens quaternary structure (the general orientation of the various structures) together, is a weak system of non-covalent (the atoms do not literally share the electrons as they would in an actual bond.) interactions. Since these interactions are inherently weak, it doesn’t take much energy to break them.
I appreciate the replies; I really do. But, these aren’t the kind of answers I’m looking for. Why are the bonds weak? Is there some other purpose? Like if all organisms could survive on Venus the world would be overpopulated? I’m looking for an explanation like that.
PS - I only have 7 more hours to post for free. So I’d like to get the responses (especially the God one) ASAP.
Well why would they? Life is usually busy competing with itself for the resources in an ecosystem, effort expended preparing for an extreme which rarely of never occurs is not available for the more immediate struggle. Neither God nor evolution has much use for a cell that lives at 400 F on this planet, so there aren’t many.
The problem you are running into is that you are asking a “why” question, while seeking a scienific answer.
Science rarely, if ever answers “Why”, that is for philosophers and theologians. Science describes “How” things happen.
You are doing the equivelent of asking “Why did God make the sky blue?” and then rejecting the answers on scattering due to wavelength, as not applicable to your initial question, which I agree it isn’t, but you should be asking a theologian why proteins behave according to physical/chemical laws, instead of worrying that the answers you have recieved(all good, by the way) don’t meet your criteria.
Regards,
FML
(and by the way, buy a membership… it costs less than 5 visits to Starbucks, and provides a LOt more long term satisfaction!) (No slur on Starbucks intended, btw)
Dunno about “good.” But, as an atheist, I’d be rather hypocritical if I couldn’t offer my personal guarantee that God doesn’t exist, now wouldn’t I? 
That would be a spurious justification. People have offered up explanations for how cells fail at temperature extremes; they “Why?” is beyond science, and in my experience, also beyond theology or philosophy to offer concrete, testable reasons. Looking for “purpose” in Nature is an ever spiraling journey into wider discovery, not narrowing resolution.
You get what you pay for. And you’re getting more definitive, or at least useful, answers here that you’ll get from a priest, a rabbi, or an imam at any price.
Stranger
That’s probably because there isn’t any, of course. There’s no more of a purpose for us to be here than for any other plant or animal. Purpose implies direction, and there’s just no good evidence for that.
You can make proteins tougher by adding pairs of charged amino acids, disulfide bonds, or particular sequences of amino acids, but doing any of that has a cost in terms of decreasing the flexibility the structure. Many enzymes derive some of their catalytic efficiency from relative motion of their various parts. If you glue them all up tight, they don’t work as well. Of course, glued up tight, they might work better under extreme conditions, but there’s no evolutionary payoff in working well under conditions that are never experienced.
Agreed. “Purpose”, such as it is, is only in the sense of adapting and thriving under the inexorable laws of nature or being extinguished. Any teleological argument ends right where it starts; with an appeal to faith beyond reason or provability.
Stranger
This could get really fun, really quick.
Cells are not heat resistant because sulfur smells bad and if we were heat resistant, people living in volcanoes would be puking all day.