Chemistry and Life

Discussion in 'General Philosophy' started by Frud11, Feb 12, 2008.

  1. Frud11 Banned Banned

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    Long ago, in a lecture room far away, my Bio prof once said: "Life is just chemistry". (a Dr. Daniel, wonder what he's been up to?)

    Well, a reaction in a test-tube is chemistry. Is Life a test-tube?:bugeye:

    I would say that Life is chemistry and the structure that the chemistry "plays out" on. Without the structure, the chemistry wouldn't be purposive, in the sense that the purpose of life and its chemistry is (just) a way of harnessing the nature of energy to disperse (scatter), by trying to "un-disperse" it, or gather energy.

    It can't push energy back uphill, but it can capitalise on its tendency to move downhill, by slowing the flow, so to speak. It gets to the bottom eventually, but the "idea" is to replicate before it does.
    Life has managed to cling to the hillside, but the inefficient thermodynamic processes, and cycles involved mean the "slowdown" only lets it sit so high. So it gets bigger, or it gets together, and manages to appear like its gone a bit higher, but this isn't really true, because of the (thermal) limit that things like enzymes, and the surface tension and conformality involved have. Life "wastes" a lot of energy.

    It's always a trade-off: energy has to be "gathered", and also used to gather. Expending and conserving energy is the process. Unique "agents", like enzymes and electron donors and acceptors (co-enzymes), and especially the structures they maintain and function within and as a part of, is the "basis". Life builds itself a test-tube, and rides in it (down the hill)...

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  3. Enmos Valued Senior Member

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    I agree with this mostly.
    I don't agree with your notion that life has a purpose however.
     
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  5. Frud11 Banned Banned

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    OK. Put slightly differently: does life exhibit purposive behaviour? Do lifeforms exhibit behaviour, and is it purposive, or purposeful? This is not asking if Life has a purpose, that's a philosophical issue.

    My Biochem lecturer (R.M. Daniel: now a fully-fledged professor, no less), was being a bit off-hand with his comment. Life is more than chemistry in some kind of test-tube, because there's also an information store (genetic material) along with all those cycles and reactions.

    DNA/RNA is like a library that gets updated and modified, and maintained (errors are "corrected" with repair enzymes). But we know that genetic material changes over long periods. Variability, of the genetic material, and of the proteins that get produced, is important.
    There is, at least in advanced organisms, a lot of material that doesn't appear to have any purpose ("junk" DNA). Although this extra material isn't read and then used to make any proteins, it still gets conserved during mitosis, so the evolutionary process must have some "reason", for faithfully reproducing it. Is it some kind of "ancillary" store, that provides evolution with "raw information"?

    DNA/RNA is the store of material that, when it gets transcribed and used to manufacture protein chains, the result is an individual organism, or phenotype.
    A phenotype is a mapping, or projection of genetic information. Eukaryotes require a "package" (most prokaryotes have this packaging ability too), that contains the genetic information, and sufficient structure and supporting "chemistry" (including a store of energy), to start up the growth process - replicating itself via cell division (mitosis).

    Viral particles are a kind of minimal package of genetic information, with sufficient structure and function to get inside (invade), a cell of a prokaryote or eukaryote. It's a kind of "one-shot" - a virus has just one opportunity, one method and a "reduced" set of genes. If it successfully crosses the barrier (this is where its structure and some of the minimal store of energy gets used), then it simply presents its genetic material, and the now invaded cell will treat this material like any other, and start producing proteins from the viral "information".

    Once there is a handful of viral enzymes, the virus can co-opt the cellular replication mechanism, and direct it to produce viral copies (by "inserting" multiple copies of itself into the replication process, with the aid of the viral enzymes). A virus is like a program that ends up diverting the "normal" cellular activity and "making" the cell reproduce viral particles. Eventually, the cell loses the ability to do anything other than reproduce viral genetic information. Once the cell is totally co-opted, it uses up its ability to do anything "normal" and more or less burns out. Cellular death ensues: the cell denatures (bursts), and releases thousands of newly-minted viral particles. A viral infection is like a chain reaction.

    There's an information-theoretic side of genetic material, and DNA/RNA "information entropy". Proteomics is also part of the pattern, so it isn't just some combination of nucleotide bases, it's a complex language, or alphabet of messages - there are 20 amino acids, a single gene can yield different variations of protein. Protein folding is important to functionality, so there's a shape "alphabet" too (the folding is believed to be influenced by enzymes). It's a big show, people.

    Is a virus a kind of organism that has minimised its "purpose" and structure, in order to be as efficient as possible at cell invasion, because the rest of the process is something that happens courtesy of the host cell? Or is it more likely that viral form and function arose alongside the evolution of the prokaryote/eukaryote line?
     
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  7. marnixR in hibernation - don't disturb Registered Senior Member

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    one of the main characteristics of life is that it reproduces
    one of the byproducts of this characteristic is the emergent property of apparent purposefulness
     
  8. Frud11 Banned Banned

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    OK. But I have to ask: is apparent purposeful "behaviour", the same as purposive function? That is, does life function purposefully, or is it that it only "appears to"?

    I don't think the distinction actually counts...or there isn't a distinction: i.e. "the property of apparent purposefulness" appears for the straightforward reason that lifeforms are purposeful...?
     
  9. Enmos Valued Senior Member

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    You have to make the distinction between what looks/is purposeful to us and what actually is purposeful objectively.
     
  10. Frud11 Banned Banned

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    I look at it like this: A stone on a hill isn't purposeful, except it might start to roll down the hill, then its apparent purpose is: "to roll". I can roll down a hill, too.
    So how is it that we recognise an inanimate object (as not-alive), and we recognise not-inanimate objects, as alive?
    What do we discriminate? I'd say it could be connected to the way things move. If a rock or stone rolling down a hill tried to stop rolling, or move back up the hill, that would be "odd", or even "strange". Why isn't it odd or strange if some "organism" does it?

    Is a virus a "special" kind of rock or stone, that can "roll" a certain way, or is it a "minimised" lifeform? Is it animate or inanimate "information"?
     
  11. Enmos Valued Senior Member

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    The ability to interact with the environment does not spell purpose.
     
  12. Frud11 Banned Banned

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    What is "the ability to interact" with the environment? What does spell purpose?
     
  13. Enmos Valued Senior Member

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    Nothing spells purpose, or anything you want.
     
  14. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    This thread belongs in Philosophy area, not biology. To see what a discussion of chemistry and life should be take a look at:
    http://www.sciforums.com/showthread.php?t=77556

    What has chemistry to do with "purpose of life"? All the posts, including the OP, speak more of purpose than biochemistry. Not even one biochemistry process or equation has appeared!
     
  15. Enmos Valued Senior Member

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    Well that's kind of what the disagreement is about.
     
  16. Vkothii Banned Banned

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    There is only disagreement if there's a conflict of meaning or interpretation.
    Chemistry is interaction. Biochemistry is interaction that "causes" or is "caused by" living things.
    Purpose is a problematic word. Most people seem to connect it with some "higher design" concept, then they accuse the person who used it with doing just that; well, that's what usually happens. Stick a pronoun in front of it and suddenly we go straight to the spirit world (without crossing a river, even). Or we're waiting for Santa Claus to arrive.
     
  17. lowefly Registered Senior Member

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    How do you waste energy?
     
  18. Vkothii Banned Banned

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    I look at energy and waste like this, son: a virus doesn't waste any (because it gets a host cell to do the job). A virus only needs to carry enough energy around to get inside, like having the right change for the bus. Ordinary old lifeforms keep handing over too much, or converting it into other currency and back again (in case they need to use it, but if they don't they try to convert it back into a more stable "currency").
     
    Last edited: Feb 15, 2008
  19. Vkothii Banned Banned

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    Life is chemistry with a purpose.

    1) The purpose of life and its chemistry is (just) a way of harnessing the nature of energy to disperse, by trying to "un-disperse" it, or gather energy.
    2) There is, at least in advanced organisms, a lot of material that doesn't appear to have any purpose ("junk" DNA). Although this isn't used to make any proteins, it still gets conserved during mitosis, so the evolutionary process must have some "reason", for faithfully reproducing it.
    3) Isn't a virus a kind of organism that has minimised its purpose and structure, in order to be as efficient as possible at cell invasion?

    And:
    The maintenance of genetic material is purposeful, the variability of proteins transcribed from it fulfils the purpose of having diverse functionality (better equipped organisms, able to deal with environmental changes), and reproductive ability.

    N'est ce pas?
     
  20. Enmos Valued Senior Member

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    Purpose implies meaning to someone/something.
    Purposeful to who/what ?
     
  21. Vkothii Banned Banned

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    Erm, life is purposeful to itself...?
     
  22. Enmos Valued Senior Member

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    lol right.. so what does that mean. Life only having purpose to itself means it hasn't got any significance.
    I agree.
     
  23. Vkothii Banned Banned

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    The significance of purpose to, say, a worm wriggling around in the soil, is that it "needs" to be purposeful about finding food, reproducing, etc (same for any bacteria in the same soil). Same principle for all life. The "meaning" of purpose isn't dependent on the purpose itself.

    Purpose doesn't have a "value" as such, except we humans consider the value of things.
    You can distinguish a wriggly worm or some insect from a lump of rock. How can you do this; what can you see that tells you "it's a live worm"? My guess is that worms behave with purpose, and rocks don't. Purposeful behaviour signifies something to us (and other lifeforms that need to eat things and escape from danger).

    A flag is significant, a book or a speech is significant.
    Significance is also a philosophical issue.
     
    Last edited: Feb 17, 2008

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