What causes death and how can we prevent it?

[superweirdo]

Hi, I was wondering that what causes a man to die, naturally. If he is constantly being damaged then how do young kids get better day by day rather than getting more sick. If it is b/c after a certain age, our cells stop growing(not reproducing), then why is that? What causes it to?

 

[Mattara]

Hi, I was wondering that what causes a man to die, naturally. If he is constantly being damaged then how do young kids get better day by day rather than getting more sick. If it is b/c after a certain age, our cells stop growing(not reproducing), then why is that? What causes it to?

Well, cells never stop re-produce, even after death. Nails and hair grow after a human has died, if so for a minute.

When a cell is dividing it sometimes mutates. The figure is 1 mutation / 10.000 cell divisions. Some of this mutations can be taken care of, but others cannot. As the cell division moves forward, more and more mutations and damages (from the oxygen we breath among others) builds up (look at the skin of elderly for example) and in the end, it cease to function and you die.

That was a short explanation as a general overview.

 

[NoTime]

Well, cells never stop re-produce, even after death. Nails and hair grow after a human has died, if so for a minute.

I do think that this is an old wives tale.
As I understand it the skin dessicates and shrinks
giving the apperance of some growth occurring.
All the cells will be dead by the time the body hits room temperature.

When a cell is dividing it sometimes mutates. The figure is 1 mutation / 10.000 cell divisions. Some of this mutations can be taken care of, but others cannot. As the cell division moves forward, more and more mutations and damages (from the oxygen we breath among others) builds up (look at the skin of elderly for example) and in the end, it cease to function and you die.

That was a short explanation as a general overview.

I think what Mattara is talking about here is called the Hayflick limit. If everything else worked perfectly then, as I understand it, you might live to be about 130yrs based on this.

However, cells have DNA locking/unlocking mechanisms (methialation sp? but there is more than one). These determine if a cell is a heart cell or a liver cell for example. Over time these locks/unlocks get inappropriately applied. Perhaps, the responsible molecules leak from cell to cell, but as I understand it nobody quite knows why. After a while a heart cell isn't quite a heart cell and a liver cell isn't quite a liver cell.
When enough of this kind of damage accumulates systems fail and you die.

Its been a while since I looked at this stuff so this may not be 100% correct or its out of date.

 

[superweirdo]

What about the myth that poeple used to live for about 500 years? What about the other myth about the scientists that claim that they can keep a human alive for a 1000 year if they can keep him locked in a room.(perfect condition, no scratches, wounds, perfect circulation, etc.) Are they just myth?
Btw, is it possible in some age for scientist to fix or stop mutation?

 

[superweirdo]

Life

What is the diff. b/w alive and dead. If you put all the organs together, life doesn't start. What causes life?

 

[Mattara]

What about the myth that poeple used to live for about 500 years? What about the other myth about the scientists that claim that they can keep a human alive for a 1000 year if they can keep him locked in a room.(perfect condition, no scratches, wounds, perfect circulation, etc.) Are they just myth?
Btw, is it possible in some age for scientist to fix or stop mutation?

That is highly unlikely as there are many different types of mutations resulting from radiation, chemicals or spontaneous.

 

[arildno]

What is the diff. b/w alive and dead. If you put all the organs together, life doesn't start.

how do you know that?
Just because you haven't found a clever way to do so, it doesn't follow that others won't ever be able to do just that.

 

[NoTime]

What is the diff. b/w alive and dead. If you put all the organs together, life doesn't start. What causes life?

A dead organ is a dead organ.
It might look much the same but all the working bits have been destroyed.

I might point out that there are transplants. Much like what you are talking about but on a smaller scale.

 

[Another God]

Because life is cellular. Cells are molecular. If you pull the organs apart, the lung organ can't provide oxygen to the blood cells which then can't provide oxygen to the brain cells, the brain cells stop respiring and hence stop producing energy which allows them to continue replicating RNA/DNA and producing proteins. Without their DNA, RNA and proteins they can't maintain their cellular machinery and waste will acumulate, errors will accumulate and they will die (Necrosis). This will eventually result in waste and crud spilling out of them harming the other cells around them which are also suffering a similar fate.

This will happen all throughout the body. No cellular function = No life no matter how well you stick the dead celled organs together.

In other words, Missing organ(s) => Insufficient nutrients/oxygen/other to the cell => Problems with cellular machinery => cell dies => organ can't work without working cells => body can't work without organs => Death

Shane

 

[Another God]

What about the myth that poeple used to live for about 500 years? What about the other myth about the scientists that claim that they can keep a human alive for a 1000 year if they can keep him locked in a room.(perfect condition, no scratches, wounds, perfect circulation, etc.) Are they just myth?

Complete Myth. Being alive is deadly. Trying to extend lifespan is actively pursued these days more than ever. if you are interested in the quest for eternal youth, then www.imminst.com is the focal website for that.

The Hayflick limit is a consideration, but that really isn't the cause of our lifespan limitation or even our aging. Cell replication limits are actually a protective adaptation (most likely against cancer). The cells can easily overcome the cellular division limit (..for instance..cancer cells). The reason we age is more commonly attributed to oxygen radical damage linked with (causing as well) mutations of the DNA, mutations of proteins causing accumulation of waste products in each cell and slowly building chain reaction coming from these problems. But the fact is that we still don't know exactly why we age (thats my objective.. to figure that out).

Can we stop mutations? No way. Can we repair them? Well the body certainly does all the time, but mistakes will be made, and wastes willa ccumulate and you can't do everything perfectly ever. The best chance we have is finding some way to 'purge' the system on a regular basis, or something like that. See, life does this by creating generations. Every new baby comes from one clean cell. The cell has been created from two cells of unique DNA combination which is generally "Clean" of all waste products and harmfull components. You can't say it has no mutations, because it IS the prototype. So it sets the basis. If its DNA doesn't manufacture a working organism, then it will die and life wil have to try again.. If it does produce a functional organism though, you have just got another lifespan of time from this species.

If we could someway replicate this purging process in our own bodies without giving up our conscious continuity...then we could be eternally young.

Shane

 

[superweirdo]

Is there a way though to put together organs and make a living being?(theoretically)

 

[arildno]

Since dead organs have undergone apotheosis on a cellular level, and bacteria have nibbled on it, and shat in it (called "rotting"), these processes would have to be reversed before the organs are potentially functional.

 

[superweirdo]

If that's the fact then why is mutation so predictable? How come everyone starts aging almost the same age?

 

[superweirdo]

no no no, implying that they have been frozen. Oh forget about it, assume this situation, somebody has just passed away b/c of heart attack, now if you replace his heart, and may be brain coz it was damaged, would he be able to come back even though his organs right now are just fine. No, why?

 

[arildno]

Water, when frozen at a normal rate CRYSTALLIZES.
What do you think happens to the membranes&interior machinery of the cell when thousands of sharp spikes suddenly pierces into them?

 

[superweirdo]

I told you, forget about freezing, concentrate on my suppose thing, that really nails my point down.

assume this situation, somebody has just passed away b/c of heart attack, now if you replace his heart, and may be brain coz it was damaged, would he be able to come back even though his organs right now are just fine. No, why?

 

[NoTime]

no no no, implying that they have been frozen. Oh forget about it, assume this situation, somebody has just passed away b/c of heart attack, now if you replace his heart, and may be brain coz it was damaged, would he be able to come back even though his organs right now are just fine. No, why?

If anybodys coming back, it would be the person whos brain it is.

 

[superweirdo]

So you are saying you can back bring dead back to life, I am sorry but besides the zombie phenomenon, this is the first. YOu should really try it, it will make a millionare. Get real man. YOu can't do that, once a person is dead, he stays dead. The only case I have heard of a person coming back from dead is when died by freezing and then brought back to life 4 days after that. But that is a popular phenomenon, has happened couple of times. But what you are saying, replacing braines, do you know how revolutionary that can be. All I am saying is that it can't be done coz if it could have been, all those funds havn't had gone to a waste. All I want is the reason of why it can't be done.

 

[Moonbear]

All I want is the reason of why it can't be done.

Arildno and Another God have supplied this answer already. Energy is required to maintain the biochemical reactions that support cellular and organ functions. When that energy supply is stopped, cells begin to undergo different biochemical reactions, and deteriorate. Once the damage is done, it's not reversible. The heart and brain are usually focused upon when determining that death has occurred, because the failure of those organs rapidly results in failure of all the other organ systems. Otherwise, a single organ failure can be survived through transplants, as long as it can be replaced before other effects have built up to damage more organs, such as building up of toxic waste products in the body following liver failure.

Once a person or other animal has died, decay of the tissues sets in quite rapidly, which is why they can no longer be revived.

As best I can tell, this is the answer to the question you're asking. If you're instead asking what makes something alive, then I'm afraid we do not have an answer for you. You might find it of interest to discuss under the subject of philosophy, but biology doesn't yet provide that answer.

 

[arildno]

He evidently believes in the existence of a mysterious spark of life that is somehow independently existing from fully functional, but inert organs.
(Those CAN be brought into "life" again, as medical transplants show).

 

[Mattara]

As a side note to the "freezing". This does work, although not with humans (or any other animal for that matter). If you freeze a living item, its cells will die, as said above. However, if you do this to a speciment of bacterias, it does not matter if some of the bacterias die, as you can use the ones that survived. Also not that this isn't a permanent soultion.

 

[arildno]

If that's the fact then why is mutation so predictable?

Predictable in what sense??

How come everyone starts aging almost the same age?

They don't.

60-year olds today look about as 40-year olds a few generations back.

Diet and medicines are to extremely important factors influencing the aging process of the body.

 

[selfAdjoint]

Predictable in what sense??

They don't.

60-year olds today look about as 40-year olds a few generations back.

Diet and medicines are to extremely important factors influencing the aging process of the body.

THis is not quite so. Pictures of people of the late 18th century at various ages (for example Benjamin Franklin, but the case is much more general) show them looking just about the way modern people look at those ages. The same is true for the busts of Roman emperors. The difference in modern demographics is not caused by differential aging but by differential death rates. Many more people died young, because of primitive, ineffective medicine, but those who survived aged just about as we do know. I am currently reading about Jefferson's last years; he died in his 80's and for the last fifteen years or so he suffered from hardened prostate and arthritis, something men still suffer, but he was generally active and went for horse rides nearly every day in his 70's.

About the only evolution that has taken place in humans^* since the ancient egyptians and sumerians is in resistance to disease. Descendents of Europeans, who were swept repeatedly by epidemics, have a good deal of immunity form being descendents of the survivors.


^*Of course there is the theory that Ashkenazi Jews evolved enhanced intelligence from being confined to occupations like money changing which required it.

 

[selfAdjoint]

I told you, forget about freezing, concentrate on my suppose thing, that really nails my point down.

assume this situation, somebody has just passed away b/c of heart attack, now if you replace his heart, and may be brain coz it was damaged, would he be able to come back even though his organs right now are just fine. No, why?

Well that's too complicated for today's science, but consider these straws in the wind.
1) Decades ago scientists took viruses completely apart, into their chemicals, and then put the chemicals back together and the viruses picked up where they left off. Of course viruses are not generally considered to be alive, but still...

2)Craig Venter, one of the big names in the human Genome project, has a new project. He wants to take a very simple bacterium, remove its DNA (thus killing it) and then insert artificial DNA of his own design and manufacture. He hopes and expects that when he gets the bugs worked out, the bacterium, or rather the frankenbact he has created, will come to life and do whatever its desgner DNA tells it to, like manufacture a rare peptide or digest garbage and produce methane, or whatever.

This is a very poor time in history to be hanging your hat on the old "difference between a live body and a dead one" conundrum. If you go into molecular biology and shine, you might be able to work in Venter's lab building a designer nematode worm.

 

[Another God]

If that's the fact then why is mutation so predictable?

Well, just like the half life of a Uranium atom there is no predictability from moment to monet, but you take a billion of them and watch them over a billion years and you can see a patter.

You take a few billion cells and watch them over the course of 80 years and there is a definite 'half life' of mutation... I don't know of any mathematical formula for it, but mutation most certainly happens and happens consistently throughout life.

 

[Another God]

2)Craig Venter, one of the big names in the human Genome project, has a new project. He wants to take a very simple bacterium, remove its DNA (thus killing it) and then insert artificial DNA of his own design and manufacture. He hopes and expects that when he gets the bugs worked out, the bacterium, or rather the frankenbact he has created, will come to life and do whatever its desgner DNA tells it to, like manufacture a rare peptide or digest garbage and produce methane, or whatever.

This is a very poor time in history to be hanging your hat on the old "difference between a live body and a dead one" conundrum. If you go into molecular biology and shine, you might be able to work in Venter's lab building a designer nematode worm.

Awesome! Can't wait to see that happening...

 

[NoTime]

2)Craig Venter, one of the big names in the human Genome project, has a new project. He wants to take a very simple bacterium, remove its DNA (thus killing it) and then insert artificial DNA of his own design and manufacture. He hopes and expects that when he gets the bugs worked out, the bacterium, or rather the frankenbact he has created, will come to life and do whatever its desgner DNA tells it to, like manufacture a rare peptide or digest garbage and produce methane, or whatever.

Bugs out? Pun intended?

I'm not sure I see a big difference from the current crop of designer bacteria.
Is there really enough current knowledge to attempt to select out the bits and pieces required to operate the cellular machinery in a selected environment?
Writing natures equivalent of a computer BIOS, that's impressive.

 

[Another God]

I actually doubt we will be able to achieve it anytime in the next couple of decades. I could be wrong of course, but last time I heard we were still pretty clueless when it came to methylation and gene silencing/activation... Even if we could use our knowledge of complete genomes to figure out what genes were needed...how it is put together in an actual living cell has already proven to be far more complicated than just base pair sequence.

Shane

 

[selfAdjoint]

Bugs out? Pun intended?

I'm not sure I see a big difference from the current crop of designer bacteria.
Is there really enough current knowledge to attempt to select out the bits and pieces required to operate the cellular machinery in a selected environment?
Writing natures equivalent of a computer BIOS, that's impressive.

Using naturally jiggered bacteria has come a long and wonderful way. Eli Lilly has been using some of those to produce human insulin for a decade now. And my exmaples were suggested by that experience, but obviously having a dedicated metabolism will only improve the economics of doing this stuff.

Venter is looking at very simple bacteria to start; there are a couple that live in our bodies. One is passively attached to the tissuel walls deep in our lungs and the other does the same in our urinary tracts. They "keep their heads down", metabolize the yummy molecules that come their way and try to avoid the attention of more vigorous and hungry bacteria. Their genomes have simplified (because there is an adaptive edge for running on the lowest energy possible) to where they have ~500 genes and maybe a thousand proteins tops. So the complexity level is just doable. But they do metabolize and reproduce, so they're unquestionably alive.

 

[NoTime]

I'd be impressed if he just got one to metabolize.
Reproductions good for propagating life, but I don't see this as necessary part of a definition of life.

Wonder if gene silencing/activation play a significant role in this model. If it does, then unless there have been some real breakthroughs lately, I doubt that it will work.

 

[Rade]

...Craig Venter, one of the big names in the human Genome project, has a new project. He wants to take a very simple bacterium, remove its DNA (thus killing it) and then insert artificial DNA of his own design and manufacture. He hopes and expects that when he gets the bugs worked out, the bacterium, or rather the frankenbact he has created, will come to life and do whatever its desgner DNA tells it to, like manufacture a rare peptide or digest garbage and produce methane, or whatever.

Excellent. This falls right in line with the definition of "life" that I posted elsewhere, here modified--"life = self generated action regulated by nucleic acids". Using this definition viruses are living entities--types of cellular parasites. I would predict that Venter could also use RNA in his line of experimentation. As to death--as a thing it does not exist, it is nothing more than the condition called "absence of life". Death derives from life, thus many entities exist that have absence of life but are not dead--proton, neutron, electron, etc.

 

[NoTime]

"life = self generated action regulated by nucleic acids".

Naa. "regulated by nucleic acids" is neither sufficient or necessary.
"self generated action" is close, but incomplete.

I would go for something like "repeated action locally decreasing entropy".

I will agree with your definition of death.

One could say computers have the same kind of life that viruses do.
They even reproduce through host machinery, evolve to changing host parameters and are often inert.

 

[selfAdjoint]

Excellent. This falls right in line with the definition of "life" that I posted elsewhere, here modified--"life = self generated action regulated by nucleic acids". Using this definition viruses are living entities--types of cellular parasites. I would predict that Venter could also use RNA in his line of experimentation. As to death--as a thing it does not exist, it is nothing more than the condition called "absence of life". Death derives from life, thus many entities exist that have absence of life but are not dead--proton, neutron, electron, etc.

Here is a BBC story on Venter's research in this field, it seems they're calling it sythetic genomics.

http://news.bbc.co.uk/1/hi/sci/tech/4636121.stm

 

[Rade]

Naa. "regulated by nucleic acids" is neither sufficient or necessary. "self generated action" is close, but incomplete.

I would go for something like "repeated action locally decreasing entropy".

But, your "repeated action" is nothing more (or less) than actions regulated by nucleic acids. Tell you what, cite one form of life that exists on Earth that does NOT have nucleic acids as the ultimate cause of your repeated actions, and I will consider your definition valid.

 

[Rade]

Here is a BBC story on Venter's research in this field, it seems they're calling it sythetic genomics.

http://news.bbc.co.uk/1/hi/sci/tech/4636121.stm

Thank you--he also has a web page for his non profit company--200 employees:
http://www.venterinstitute.org/

 

[NoTime]

cite one form of life that exists on Earth that does NOT have nucleic acids as the ultimate cause of your repeated actions.

I did do just that
Perhaps you do not like my example, but that's an entirely different argument.

My biggest objection to your definition is the fact that life is the only thing that generally violates the law of entropy.
I would think that this feature would be required in the definition of life.

 

[arildno]

THis is not quite so. Pictures of people of the late 18th century at various ages (for example Benjamin Franklin, but the case is much more general) show them looking just about the way modern people look at those ages. The same is true for the busts of Roman emperors. The difference in modern demographics is not caused by differential aging but by differential death rates. Many more people died young, because of primitive, ineffective medicine, but those who survived aged just about as we do know. I am currently reading about Jefferson's last years; he died in his 80's and for the last fifteen years or so he suffered from hardened prostate and arthritis, something men still suffer, but he was generally active and went for horse rides nearly every day in his 70's.

About the only evolution that has taken place in humans^* since the ancient egyptians and sumerians is in resistance to disease. Descendents of Europeans, who were swept repeatedly by epidemics, have a good deal of immunity form being descendents of the survivors.


^*Of course there is the theory that Ashkenazi Jews evolved enhanced intelligence from being confined to occupations like money changing which required it.

Not really.
Please remember that those you are looking at (for example busts of emperors) are those that had access to the TOP-QUALITY food in their society. Also remember that compared to previous dietary regimes, the lower middle classes of the Western world today eat the food of emperors on a daily basis.

 

[Another God]

Using this definition viruses are living entities--types of cellular parasites.

The "viruses aren't living because they need cells to replicate" argument has never seemed sufficient to me. The same argument could be stated "Humans aren't living because they need the Earth to live off". Or any other number of obligate parasitic organisms can be defined as non-living because of this ever so simple definition.

The only reason that definition is applied to viruses is because they are so simple. Well, in relation to the ecosystem, a human is pretty damn simple too. Similarly a virus looks simple compared to a Eukaryotic cell from our perspective, but the chemistry involved is still incredibly incredibly incredibly sophisticed. Just because it is comparitively simple doesn't detract from the very repetitive and directed nature of its existence.

I think Viruses ARE an expression, an external packaging, of what life is. To be more specific, BIOLOGICAL life really is just replication of DNA and all of the other associations are just conveniences to allow genetic replication to occur in a more smooth, consistent or reliable manner.

(PS: I don't mean to define what "life is". What I mean to express is that this thing we see all around us really isn't so remarkable (I mean it is...but there's no magic involved..if you know what i mean) that there is something which makes it impossible to define. This 'life' which we are familiar with is just DNA replicating in various forms)

Hmmm, I guess in response to your original post Rabe: By my very statements above I would take your definition that step further. Life is the replication of DNA.

I could takr this concept a lot further, but I think I am just stealing all of Richard Dawkins' ideas now and making them sound like they are my own, so I will stop LOL.

Shane

 

[Another God]

Ahhhh the ramblings of a crazy person. Sorry for the non-sensical post. let me try to re-post myself with a sensible summary:

Simplicity doesn't change the function of life, and lifes function is consistent from the smallest to the largest: Replication of Nucleic Acids. The packaging of nucleic acids, and the causal relationship nucleic acids have with their packaging (proteins, lipds etc) need not be part of the definition for their only role is simply to facilitate the safe, reliable, consistent replication of nucleic acids. No matter how the DNA is packaged: In a protein case in a virus, in the cytoplasm of a prokaryote, or in the nucleus of a eukaryote no matter how that DNA is placed in a position where it can be copied (polymerase, denaturation and cooling in presence of nucleotides etc) then it acheives the goal.

Yes, a PCR machine is a short burst of life. LOL

And yes, upon reflection, this is certainly Richard DAwkins' theory. For more info, read the Selfish Gene.

Shane

 

[selfAdjoint]

Another God and Rade, isn't this just one of those endless semantic arguments? Of course the noun "Life" has big emotional connotiations for us, but just like "Species", "Race" and other big feeling nouns when you try to project its categories into real nature they blur irretrievably.

None of these concepts ar "well-defined" mathematically. People attempt well-definition, even to the point of setting up axioms, but then other people complain that those axioms fail to capture something that "everybody knows" fits into the category in question.

Even if Venter creates a synthetic bacterium, some people won't admit it's synthetic life till they see it done on cows and horses (or sheep, like Dolly; now THAT was something that convinced the public!).

 

[superweirdo]

lets get back to topic,(although we are talking about life, its not the in the sense I intended-philosophical)

someone in here earlier said that if you freeze us, our cells die, if that is true, then why are rich guys freezing their brains and bodies so if later they come up w/ a technology, they can bring them back?

 

[arildno]

Why do idiots do the things they do?
It is unanswerable, whether or not the idiot is rich or not.

 

[selfAdjoint]

Just another Venter link. This one is from 2003 but it has a very clear discussion of their plans and the difficulties. As far as I know they are still working on it.

http://www.carlzimmer.com/articles/2003/Venter2003.html

 

[Rade]

I did do just that Perhaps you do not like my example, but that's an entirely different argument.

But your computer = life example because computer does "repeated actions" makes clear why the statement "self generated action" must be part of any definition of life. That is, the computer does not assemble the information content of its software code, living entities do. Also, many non-living entities do repeated actions that decrease local entropy such as planets that repeat movement around sun instead of willy-nilly just moving randomly with large entropy.

My biggest objection to your definition is the fact that life is the only thing that generally violates the law of entropy.
I would think that this feature would be required in the definition of life.

Fair enough, as long as we are sure that no quantum machines can violate law of entropy--I have no knowledge of this one way or another. If not, then sure, we can modify my suggested definition of life as "life = self generated motion regulated by nucleic acids that results in local decrease of entropy over time"

 

[Rade]

Another God and Rade, isn't this just one of those endless semantic arguments? Of course the noun "Life" has big emotional connotations for us, but just like "Species", "Race" and other big feeling nouns when you try to project its categories into real nature they blur irretrievably. None of these concepts are "well-defined" mathematically. People attempt well-definition, even to the point of setting up axioms, but then other people complain that those axioms fail to capture something that "everybody knows" fits into the category in question.
Even if Venter creates a synthetic bacterium, some people won't admit it's synthetic life till they see it done on cows and horses (or sheep, like Dolly; now THAT was something that convinced the public!).

The science of Biology (study of life) IMO demands that some attempt be made to define the concept that is studied. This must be achieved not for communication, but for cognition, for before we can communicate the concept first must be before us a "living thing" that is the focus of our attention. I think it critical to offer definitions of the concept called life, then wait for them to be falsified, such is the way of science. Take the concept we call matter for example--it comes in many complex forms, yet it is defined as simple mathematical equation as M = E/c^2. IMO, someday a biological Einstein will derive the equation for the concept we call life.

 

[selfAdjoint]

The science of Biology (study of life) IMO demands that some attempt be made to define the concept that is studied. This must be achieved not for communication, but for cognition, for before we can communicate the concept first must be before us a "living thing" that is the focus of our attention. I think it critical to offer definitions of the concept called life, then wait for them to be falsified, such is the way of science. Take the concept we call matter for example--it comes in many complex forms, yet it is defined as simple mathematical equation as M = E/c^2. IMO, someday a biological Einstein will derive the equation for the concept we call life.

I disagree, all the scientists need to do science is a rough working definition. "What is life" is to biologists as "What is the wave function" is to quantum physicsts; something outsiders obsess about but only a few professionals ever bother their heads about.

 

[superweirdo]

After you guys are done discussing about the definition of life, could you explain to me why can't a doctor freeze the body of a person who just died and then replace his brain and heart?(depends on how he died). B/c freezing cells don't kill them, it hybernates them.

 

[selfAdjoint]

After you guys are done discussing about the definition of life, could you explain to me why can't a doctor freeze the body of a person who just died and then replace his brain and heart?(depends on how he died). B/c freezing cells don't kill them, it hybernates them.

Water expands when it freezes, unlike nearly all other materials. This property is very important for life, but it means that freezing cells runs into the problem of ice crystals bursting the delicate structures in cells. There has been a LOT of research for many decades in trying to work around this problem, but such successes as have been announced are very small scale. Fact is when you freeze living tissue and then thaw it again what you get is dead tissue.

 

[arildno]

A more viable option would be the one some bugs use:
Effectively, they empty their cells of water, and fill them with a sort of "freezing" liquid that remains in fluid state at much lower temperature.
Their metabolism and signs of life stop, even though their inner machinery is unharmed.

Once more favourable external conditions are present, they "de-freeze", and wake to life again

 

[superweirdo]

Wait a sec, is there any research going on where they are trying to put freezing liquid in our body and see what happens?(they would need some suicidal volunteer for that though). I believe that the people who want to suicide should contribute to such experiments.(not if they can be stopped but sometimes, it is too much)