Molbiogirl and Doddy were both suggesting (presupposing) that biological function had a precursor to fermentation, photosynthesis and respiration. But there is no such precursor found in the fossil record or anywhere else that I am aware of.
They and Matt P, had been referring to self replicating enzymes that rely on these systems of energy conversion and other cell processes for which they exist, and are therefore not self replicating. I made the point to molbiogirl that they are not self anything...
In message 190 you were talking about thermosynthesis, i.e. free energy gain from thermal cycling. Now that I'd like to see.
Now you're being revisionist, and invoking respiration that is still ATP dependant, and also in need of andenine for it's usual biological DNA and catalyitic functions?
Slow down... you always latch on to a response too soon. First it was self replicating DNA, and then it was viruses, then adenine was adenosine, and now this?
Stop smoking those prebiotic chemicals.
As I said to jar ealier... who cares what the source of energy is?
Your example is hardly prebiotic. But it is the best example as far as biological life goes, since it is the simplest.
You know, I really want to express my love for you guys, and that of the truth, but you've forced me to be quite adament. You're not very nice...
I dunno, you tell me -- you're the one who believes that snakes talk people into eating fruit and people turn into pillars of salt.
I could tell you what I've read about evolution, the big-bang, super-universes, quantum foam, and all that stuff. Eventually you'd ask a question I can't answer, then I'd have to go look it up. Even If I had the time for that shit, in the end you'd ask a question science hasn't answered yet. So let's save time and skip ahead to "I don't know." -- jhuger
Cell respiration is a process that arose early in the evolution of life. The first cells that experienced respiration lived in an environment void of oxygen. Some of these first organisms were called thermophiles
We define a molecular heat engine as a molecule that can convert heat into free energy when thermally cycled or when placed in a thermal gradient.
A detailed model for a molecular heat engine is constituted by the pF1 enzyme, a proposed progenitor of the homologous (1) alpha and beta sub units of the F1 moiety of the contemporary ATP synthase enzyme (2-4). In the thermosynthesis model for the origin of life, pF1 synthesizes peptide and phosphate bonds by creating a local environment in its enzymatic cavity that permits dehydration reactions. The product containing the bond has a higher free energy in water (5), and can therefore, because of energy conservation, not directly be released. Instead, it remains strongly bound, entering the medium only upon a thermal unfolding of pF1. The binding change mechanism as effected by contemporary ATP synthase (6) is identified as a relic of this so-defined thermosynthesis mechanism.
In the model the thermal cycling is attributed to - macroscopic - convection of the medium in which the pF1 is suspended. Consider as example present day F1 ATP synthase as a heat engine. The presence of nucleotides increases its unfolding temperature by ~10Â°C. The delta H for the unfolding of the individual alpha and beta subunits is ~660 kJ/mole (7-8). At an unfolding temperature of 60Â°C (330Â°K) the Carnot ratio predicts an available work of
(delta T / T) delta H = (10 / 330) 660 = 20 kJ/mole,
a value comparable with the free energy of a peptide and phosphate bond.
Using only one enzyme to begin with, thermosynthesis by a molecular heat engine allows a very simple model for the emergence of the bioenergetic chemiosmotic machinery and, more generally, for the origin of life (2-4).
Abiotic synthesis of organic compounds from carbon disulfide under hydrothermal conditions, Rushdi AI, Simoneit BR, Astrobiology, 2005 Dec;5(6):749-69
Abiotic formation of organic compounds under hydrothermal conditions is of interest to bio, geo-, and cosmochemists. Oceanic sulfur-rich hydrothermal systems have been proposed as settings for the abiotic synthesis of organic compounds. Carbon disulfide is a common component of magmatic and hot spring gases, and is present in marine and terrestrial hydrothermal systems. Thus, its reactivity should be considered as another carbon source in addition to carbon dioxide in reductive aqueous thermosynthesis. We have examined the formation of organic compounds in aqueous solutions of carbon disulfide and oxalic acid at 175 degrees C for 5 and 72 h. The synthesis products from carbon disulfide in acidic aqueous solutions yielded a series of organic sulfur compounds. The major compounds after 5 h of reaction included dimethyl polysulfides (54.5%), methyl perthioacetate (27.6%), dimethyl trithiocarbonate (6.8%), trithianes (2.7%), hexathiepane (1.4%), trithiolanes (0.8%), and trithiacycloheptanes (0.3%). The main compounds after 72 h of reaction consisted of trithiacycloheptanes (39.4%), pentathiepane (11.6%), tetrathiocyclooctanes (11.5%), trithiolanes (10.6%), tetrathianes (4.4%), trithianes (1.2%), dimethyl trisulfide (1.1%), and numerous minor compounds. It is concluded that the abiotic formation of aliphatic straight-chain and cyclic polysulfides is possible under hydrothermal conditions and warrants further studies.