Theoretical origin of life; energy needs of first cell (Introduction)

by David Turell , Wednesday, May 13, 2020, 21:33 (1655 days ago) @ David Turell

A highly theoretical discussion:

https://evolutionnews.org/2020/05/on-the-origin-of-life-here-is-my-response-to-jeremy-e...

"England rightly states that the fluctuation theorems allow for the possibility that some mechanism could drive matter to both lower entropy and higher energy (higher free energy), thus potentially solving the problem of the origin of life, at least in theory. In contrast, I addressed the likelihood that, given the practical constraints, realistic natural processes on the early earth could generate a minimally complex cell. In that context, England indirectly affirmed the main points of my argument and thus reinforced the conclusion that an undirected origin of life might be possible in principle, but it is completely implausible in practice.

"1) The main points of my argument can be summarized as follows:
Natural processes tend to drive systems toward higher entropy, lower energy, or both. In direct conflict, the origin of life requires a collection of molecules to move toward dramatically lower entropy and higher energy.

"2) The only way to overcome the thermodynamic barriers is for an engine to be present at the very instantiation of life that can convert some available source of energy into a form that can fuel the construction and operations of a cell.

'3) Significant quantities of information must also be present both to steer a highly specific set of interconnected chemical reactions that comprise a minimally viable cell and to direct the generated energy toward powering the otherwise nonspontaneous reactions.

***

"The role of information in the simulation is more subtle and calls for a brief digression into information theory. A key tenet is that information can often be thought of as that which enacts causal control over or reduces the uncertainty in an outcome. In the case of the experiment, the highly specified construction of the simulation entails the implementation of information. The applied information constrains the dynamics (reduces the uncertainty) to effect a specific category of outcomes. It functions equivalently to the information in an enzyme that directs the production of a specific molecule.

***

"These specifications represent applied information that constrains the dynamics in such a way as to produce the desired results. Here again, achieving noteworthy behavior requires an energy converter and the application of information.

***

"The constraints governing an emerging cell present even greater challenges than in the cited experiments for nature to assemble a viable engine. In life, the energy produced must be in the form of high-energy (energy-currency) molecules that could power the chemical reactions undergirding cellular operations. The challenge is that the energy requirement is enormous. As I explained in my article, the minimal power production capacity needed for a nascent cell just to prevent it from degrading into simple chemicals approaches, if scaled, that of a high-performance racing car.

"The most promising candidate for a “natural engine” is proton flows across thermal vents that theoretically could generate high-energy molecules. However, simulations of vents under ideal conditions only produce chemical energy at a rate that is at least eight orders of magnitude too small. And the actual product is formaldehyde in concentrations far too miniscule to contribute to any stage in the genesis of a cell. Such meager results simply highlight the fact that no natural mechanism could realistically generate the required energy to power even the earliest stages of any origin-of-life scenario.

"Moreover, the driven objects in each of the cited experiments are identical, so they all interact uniformly with the applied field. In contrast, the reactions in a cell are quite different. As a result, no single engine could drive more than one or two of them even under ideal conditions. Consequently, a cell requires multiple mechanisms to extract the energy from the energy-currency molecules and direct it toward powering each distinct reaction. I detailed in my article how only a suite of hundreds of enzymes could meet this requirement, which corresponds to at least a million bits of information. England’s response to my article has only reinforced these conclusions." (my bold)

Comment: The takeaway is simple: all the research that looks at one simple aspect of the first cell, like RNA, misses the entire point. A cell is made up of millions specifically placed amino acids, fleets of enzymes to run processes as fast as possible and lacks mitochondria, so the source of lots of energy is a problem for it. And information must be present as shown in my bold, just above.