Posted: Mar 07, 2010 8:36 am
rainbow wrote:byofrcs wrote:I like the RNA world. Some expansion on the chiral catalysts (are they random ?) and the steps to autocatalysing RNA (which we have now).
Plus shouldn't we mention the importance of phosphate as a catalyst at a number of stages (e.g. Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions. Matthew W. Powner1, Béatrice Gerland1 & John D. Sutherland).
There is a great deal of elegance in the Sutherland experiment, but it does contradict a lot of other work that has been done on the synthesis of bases and sugars prior to nucleotide synthesis, which brings us to the next part of Cali's paper:Moreover, research has established that these lipids can encapsulate RNA molecules, and selectively admit the passage of base and sugar molecules to facilitate RNA replication[54, 55].
Ribose sugar isn't that easily formed under prebiotic conditions, and some of the bases are unstable. It remains unanswered as to how they could obtain any significant concentration in the vicinity of the lipids.
Isn't this is where the mackinawite surfaces (proposed in the iron-sulphur world and using GA3P and DHAP) come into play because thus we have routes to an autocatalytic set ?. The presence of large volumes of the surfaces would allow the concentrations even in the adverse conditions of the pre-biotic environment (e.g. acidity in sea and ultraviolet).