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What came first the cell or the gene?

  1. Aug 8, 2009 #1
    Considering the thermodynamic law of entropy it would be considered impossible for a sub-infinite number of genetic combinations to code for a single cell, in light of the massive amounts of early UV radiation. Even considering genes of DNA and RNA allowed to replicate in a lab, the combinational symmetry breaks down. Without a primordial atmosphere to block out harmful UV, genetic combinations responsible for life or cellular structure could never cross the maximal capacity or entropy into an ordered ensemble. As if the cell structure came first with blueprints coded later. Most likely primitive plant cellular structure responsible for splitting CO2 into carbon and oxygen. This in-turn could produce a sustainable environment that protected the later formation of a minimal ground states of entropy or the increase in ordered states of complexity that could specify and automate the cellular machinery for future generations.
     
  2. jcsd
  3. Sep 12, 2009 #2
    without proteins/genes the cell would just be a bunch of bilayer sacs floating around. organelles wont even exist. You have to have genes/proteins structurally alter the sacs to something useful
     
  4. Sep 14, 2009 #3

    alxm

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    Well the gene would have to come first of course. I'm not sure why UV would be a problem. If UV levels at the surface were too high, life would have to have developed further down in that primordial pool.

    Just comparing procaryotes with eucaryotes would seem to make it clear that cell structure didn't come first.

    Also, RNA certainly came before DNA; DNA is synthesized from RNA. It's in fact a quite difficult chemical reaction (a radical reaction), which no doubt didn't evolve easily. But the change from RNA to DNA was necessary for complex life, since DNA is more stable in long strands.
     
  5. Sep 14, 2009 #4

    arildno

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    "Considering the thermodynamic law of entropy it would be considered impossible for a sub-infinite number of genetic combinations to code for a single cell, in light of the massive amounts of early UV radiation."

    Keep the 2.law of thermodynamics out of this, please.

    We are not talking about a closed system!
     
  6. Sep 14, 2009 #5
    You might be interested in a new recently published theory regarding the possible role of ZnS.

    https://www.physicsforums.com/showthread.php?t=334795 [Broken]
     
    Last edited by a moderator: May 4, 2017
  7. Sep 14, 2009 #6
    To add,

    1. the cell bilayer will not protect against UV. UV can go through that easily. DNA in a cell or outside a cell have the same risks.

    2. DNA in the cell is protected by various proteins, nucleosomes, blah blah that keep it wound, and other proteins keep it protected. So yes, the DNA outside of the bilayer sacs in the promodial soup might have not been so lucky than the ones that some how got taken into a bunch bilayer sacs along with proteins.
     
  8. Oct 21, 2009 #7
    reply to mazinse:
    How could the first DNA have been protected by bilayer sacks and proteins? DNA is required to form proteins.
     
  9. Oct 21, 2009 #8
    There are models of abiogenesis that places these events at a place where UV radiation cannot reach, such as the iron sulfur world, to name a popular version.

    DNA was most likely not the first replicator. There is evidence to suggest that different forms of RNA served both as replicator and catalyst, which was replaced by DNA and proteins. Thus, this idea escapes the catch 22 or chicken and egg problem of DNA and proteins.
     
  10. Oct 22, 2009 #9

    arildno

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    No.
    Where did you get that idea from??
     
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