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Thread: DNA's most fundamental form?

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    kem
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    Universal Mind John Galt's Avatar
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    I am not entirely clear what you mean by 'fundamental form', or 'able to remain intact', however here is a brief summary of the character of DNA.

    The double helix you refer to has two strands of chemical units whose backbone consists of sugars and phosphates. These provide the framework on which the bases that encode the genetic instructions are attached.
    There are four bases present in DNA, adenine, thymine, guanine and cytosine. Bases on on strand of the helix pair up with other bases on the other strand. Adenine always pairs with thymine and guanine with cytosine.
    The bases are grouped into threes, each group of three is called a codon. The codons define which amino acids are to be assembled together to form specific proteins.

    Does that help?

    For a detailed, but useful discussion of DNA consult the wikipedia article.
    http://en.wikipedia.org/wiki/DNA


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    I think what your getting at is the nucleotide. I would say that apart from the fact it can be broken into component atoms during DNA processes the building blocks are nucleotides. Which in DNA consist of a pentagonal deoxyribose sugar molecule, a base attached to one of its carbons and a phosphate to another in such an arrangement.

    O phosphate
    \/\__base
    |_|
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    Universal Mind John Galt's Avatar
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    Quote Originally Posted by kem
    can we go back to a time in history before DNA cells had ever been formed,
    Your wording here could cause confusion. Cells, the standard 'expression' of life. contain DNA. the DNA determines the character of the cell, but we would not normally speak of DNA cells.
    Quote Originally Posted by kem
    are we assuming that in the earths earlier history the conditions were too hot for these chemicals/molecules to exist,
    Not at all. Certainly the early Earth was too hot for any complex organic chemicals to remain intact, but more to the point it took a great deal of pre-biotic chemistry to get to the point where molecules of the complexity of DNA could be constructed. We are still not sure of exactly how this occured.
    Quote Originally Posted by kem
    and if this is the case are the molecules in question used for anything else meaningful or is this the only role they play?
    I am not entirely comfortable with your use of the word only. Their role in determining the character and development of life forms makes them the most important aspect of life. In one sense they are life. So to say that is the only thing they do, which it is, is rather understates their importance.
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    Forum Cosmic Wizard paralith's Avatar
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    Well, some of the molecular components of DNA also make up other molecules that serve different functions in the body, if that's what you're asking.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
    ~Jean-Paul Sartre
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    Quote Originally Posted by kem
    can i also ask about how the four chemicals we know as the DNA letters are arranged... you mention that they are paired off, but is there a connection between the 'backbone' and the four, in other words do AT connect first or GC, and does this matter?
    I'm not exactly sure what you're asking but if you're asking about if A,T,G, and C are molecules or atoms, they're molecules.

    Adenine, Guanine, Cytosine, and Thymine (lower case of course, you don't say Water). The only thing I remembered from cellular biology

    I believe I've seen the structures of the respective molecules, too.

    They pair off in a certain way because of their chemistry.

    I'm not a biochemist so I can't give you details, but I've seen a bit of it...

    I don't know about connecting "first" per se, but they connect due to their chemistry. I can't name you the reaction though.

    source

    perhaps that page helps?
    (Fe)male = male alloyed with iron for greater strength, ductility, and magnetism.
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    Forum Professor sunshinewarrior's Avatar
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    Quote Originally Posted by kem
    indeed, please forgive my wording

    i have much to contemplate

    please do not get hung up on the word - only, i was merely trying to illustrste that once the chemicals in question were 'formed' it was impossible for them to create anything but DNA
    Nice thought, and interesting if you can demonstrate it, but please be aware that most biologists today believe that DNA likely had a precursor in RNA replicators, and RNA, as we know, uses 3 out of the 4 groups that DNA does. So you are perhaps better advised to look at the four bases of RNA (a single-stranded large-ish molecule), which are Adenine, Guanine, Cytosine (as in DNA) and Uracil (replaced in DNA with Thyamine).
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    ATP (adenosine tri-phophate) is one of the 4 monomers that is utilised in DNA synthesis, however ATP is central to other functions within the cell. For example, it is the energy 'currency' that drives metabolic reactions. The ratio of ATP to ADP is used by cells to sense stress, starvation, and so forth.

    GTP (guanosine tri-phosphate) can be used as energy currency as well, albeit not very often at all, under certain circumstances.
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    Quote Originally Posted by kem
    can i also ask about how the four chemicals we know as the DNA letters are arranged... you mention that they are paired off, but is there a connection between the 'backbone' and the four, in other words do AT connect first or GC, and does this matter?
    I may be entirely misunderstanding your question.

    'A' on one backbone pairs to 'T' on a second backbone. This pairing is independent from 'G' on one backbone pairing to 'C' on the second backbone.



    The image above shows bases in purple, and the backbone indicated by an alternating arrangement of P (phosphate) and a red pentagon (sugar). There are 2 backbones on a strand of DNA, and they are on the outside, so to speak, of the molecule. RNA has one backbone (single stranded).

    The dotted lines in the the center indicate hydrogen bonds. A and T pair up, because their structure allows 2 hydrogen bonds to form between them. G and C pair up for similar reasons, except that 3 hydrogen bonds for between them.
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    Quote Originally Posted by kem
    indeed, please forgive my wording

    i have much to contemplate

    please do not get hung up on the word - only, i was merely trying to illustrste that once the chemicals in question were 'formed' it was impossible for them to create anything but DNA
    I think your answer is that they can *make* other molecules(we aren't God and neither are these chemicals so they don't *create*- one of my prof's pet peeves was saying "create") They don't automatically go for each other. But there are conditions in which they'll only form DNA. Other molecules like the one I'm working with can tag to guanine or intercolate in the DNA, etc.

    And might as well just say that 90% of the time there are side products.
    (Fe)male = male alloyed with iron for greater strength, ductility, and magnetism.
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    Please allow me to apologise for deleting my previous posts and ‘locking my account’ by giving a phoney email address (and hence been unable to access it).

    I have returned only to offer an explanation…


    Even though my contemplation achieved results, as I do not work in the scientific field, I do not have any motivation to share those results with you. If I were working in the field there wouldn’t be as much as a problem, as not only would my findings enhance my prospects of promotion etc, but I would also have access to the tools needed to prove those findings, or alternatively the tools with which to design and make products as a result of those findings.


    So I am sorry you worship a system that places obstacles to our advancement.
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    Forum Cosmic Wizard spuriousmonkey's Avatar
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    did you have any findings?
    "Kill them all and let God sort them out."

    - Arnaud Amalric

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    Universal Mind John Galt's Avatar
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    Kem, there are trained specialists who can help you with your mental problems. Use them. Good luck.
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