Ribosoids

This is the novelty that characterised the first part of postchemical evolution, and had at least one important consequence the polymerising ribosoids allowed for the first time the production of peptides and small proteins inside the system, with endogenous syntheses, instead of importing these molecules from the outside. And this switch from exopoiesis to endopoiesis was an essential prerequisite for the development of a true autopoiesis. 

In addition to polymerising ribosoids, precellular systems were producing many other types of ribosoids, and, for statistical reasons, most of these were devoid of any metabolic value. A few, however, could have more interesting properties and behave, for example, like ribozymes or transfer-like RNAs. The first part of postchemical evolution was therefore a simple continuation of the metabolic processes of chemical evolution, with the difference that precellular systems were now carrying RNAs in their interior, which means that both the players and the rules of metabolism were slowly changing. 

Polymerising ribosoids could spontaneously form aggregates of high molecular weight by self-assembly. This was a formidable mechanism because it could easily produce compounds that had dimensions in the order of 1 000 000 Da, as proved by the fact that viruses and ribosomes still achieve these dimensions entirely with self-assemby processes. 

It is known that ribosomes of different species can contain very different proteins, and yet all function as ribosomes. In this case, the same function does not require the same components, but only structures that collectively belong to a wide family of molecules. The ribosome function could reappear in new generations of ribosoids even without replication of the same molecules, a mechanism... 

This then is the solution of the ribotype theory in order to avoid the error catastrophes in the journey toward exact replication, it was necessary to have high molecular weight protoribosomes, and the production of these ribosomes for an indefinite number of generations was possible, before exact replication, because ribosoids could achieve it with processes of self-assembly and quasi-replication. The development of high-molecular-weight protoribosomes took place during postchemical evolution, simply because all necessary conditions existed in that period, and the development could be realised with processes that were both natural and primitive. 

All this tells us that the evolution of primitive ribosoids into protoribomes and ribogenomes could have produced - at equal thermodynamic conditions - a countless number of other protein worlds, and therefore countless other forms of life. In the course of precellular evolution, therefore, two distinct processes went on in parallel the development of metabolic structures, and the development of a particular genetic code that gave life the familiar forms of our world, and not those of countless other possible worlds. 

The origin-of-life scenario was instrumental for the new theory of the cell, because it led to the the conclusion that the ribotype had an evolutionary priority over genotype and phenotype. More precisely, the scenario described a precellular ribotype world (not to be confused with the RNA world) where some ribosoids could act as templates (ribogenotype), others as enzymes (ribophenotype), and others as polymerising ribosoids (ribotype) that were responsible for the growth and the quasi-replication of the ribonucleoprotein systems. 

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