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Why nucleotides when mixed together in the absence of a template RNA molecule do not readily link up into a chain? We know that the bond between nucleotides side by side is stronger than the hydrogen bond between the two RNA strands, a negative and a positive one. Shouldn't then the nucleotides form chains of RNA more readily by just attaching to each other than making a dimeric RNA through a lock and key type latching?

The book that caused this question is "What Is Life?" by A. Pross (p.68), who unfortunately doesn't provide an answer.

Denis
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The dNTPs don't just come together. They require a polymerase to break off 2 phosphates and bond the hydroxyl group to the remaining phosphate. To take a nucleotide triphosphate and add it to a growing chain of nucleic acid, the polymerase checks the fidelity of the hydrogen bonds that precede the new bond. dNTPs provide the energy for this reaction, but the enzymes require a double stranded molecule to copy. In other words, they can copy double stranded nucleic acid, but not form it from scratch.

Karl Kjer
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  • Thanks for your answer! I only would like to clarify if the same laws apply to the self-replicating RNA (autocatalytic), with no enzymes, since the book is talking about prebiotic time. – Denis Nov 26 '17 at 12:48
  • @Karl: DNA polymerase theta is capable of template-independent DNA synthesis. Kent et al. (2016) Elife 5: e13740. https://www.ncbi.nlm.nih.gov/pubmed/27311885 –  Nov 27 '17 at 09:34