Thursday, January 12, 2017

A colloidal origin of life?

Working with ideas about the origin of life and its relationship to the colloidal environment. Scientists figure that the first meaningful step toward life was the development of macromolecules from smaller molecular entities. The RNA world hypothesis posits that RNA was a good candidate for a pre-life molecule. RNA is involved in replication, it can play the role of an enzyme, and it is involved in the production of proteins, which carry out the day to day activities of the cell. All of these activities make RNA a reasonable candidate for a precursor to living cells. RNA activities suggest that it can play a role in controlling its environment. 

RNA might have developed in a meaningful way, that is, in great numbers – populations of which were able to "play around" with their environment until a replicable, sustainable system of life was formed, within the highly ionized colloidal environment of clay deposits. If this is the case then it's possible that the development of probionts, micelle-like bodies that Oparin hypothesized in the mid-1920s makes sense. It's a kind of biomimicry in reverse. That is to say the pre-life RNA molecules began to build an environment similar to the one in which they first arose, an aqueous, protected environment that provided a compartment through which they could interact with their environment. 

If we jump to the present and look at living cells we can consider them broadly as colloidal environments. Within these aqueous spaces are suspended (albeit large) particles like organelles and ribosomes. The organelles themselves can be considered colloidal because of the suspended membrane systems and proteins within them. So many biological features are colloidal. For example milk, blood, tissue systems, and all sorts of bodily fluids are colloidal in nature. 

If we extend our thinking to imagine the first replicating RNA molecules to have built an artificial colloidal  environment around themselves we may get closer to understanding why life took the forms it did and how contemporary living forms relate to our very ancient ancestors of almost four billion years ago. 

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