The great basic question of science: Membrane compartment or non-membrane phase compartment (biophase) is a physical basis for origin of life?
Matveev V.V. 2016. Comparison of fundamental physical properties of the model cells (protocells) and the living cells reveals the need in protophysiology. International Journal of Astrobiology, Page 1-8. Stable URL: http://journals.cambridge.org/abstract_S1473550415000476
Highlights 1. If life originated in seawater, the origin of the first cell inevitably comes down to the origin of the sodium pump and any structure supporting it the lipid membrane without which the work of any pump would make little sense. 2. Since the sodium-potassium pump (Na+/K+-ATPase) was discovered, no molecular model has been proposed for a predecessor of the modern sodium pump. Neither Millers electrical charges, nor Foxs amino-acid condensation, nor building ready-made biomolecules into coacervates; none of this has managed to lead to the self-origination of the progenitor of the ion pump even in favourable lab conditions. 3. In 2007, we saw the simultaneous release of two articles, in which it was posited that life originated not in seawater as previously thought, but in smaller bodies of water with a K+/Na+ ratio necessary to sustain life. In this conditions sodium pump is not needed and the pump can originate later. But why the pump is needed if K+/Na+ ratio is good? The origin of the sodium pump in conditions where there is no natural need for it may require the agency of Providence. 4. Potassium Big Bang on Earth instead of potassium ponds. 5. Fox's microspheres do not need potassium ponds. 6. Despite the fact that Fox's microspheres have no fully functional membrane with sodium pumps and specific ion channels, they generate action potentials similar to that by nerve cells and in addition have ion channels which open and close spontaneously. This ability of the microspheres contradicts to the generally accepted ideas about the mechanism of generation of biological electrical potentials. 7. Hodgkin-Huxley model of action potentials is similarly well-compatible with both the nerve cell and Foxs microsphere. 8. Biophase as the main subject of protophysiology. In the past they considered the living cell as a non-membrane phase compartment with different physical properties in comparison to the surrounding medium, and this physical difference plays a key role in cell function. According to a new take on an old phase, non-membrane phase compartments play an important role in the functioning of the cell nucleus, nuclear envelope and then of cytoplasm. Somebody sees the compartments even as temporary organelles. According to available data, the phase compartments can play a key role in cell signaling. In this historical context, studies in recent years dedicated to non-membrane phase compartments in the living cells sound sensational. 9. It is essentially a Protocell World which weaves known RNA World, DNA World and Protein World into unity. 10. In the view of non-membrane phase approach, the usage of liposomes and other membrane (non-biophase) cell models to solve the issue of the origin of life is a deadlock way of the investigation.
The great basic question of science: Membrane compartment or non-membrane phase compartment (biophase) is a physical basis for origin of life?
Can you introduce your topic in a little more detail? Defining your two alternatives and saying a little about the significant differences between them would be enough.
3. In 2007, we saw the simultaneous release of two articles, in which it was posited that life originated not in seawater as previously thought, but in smaller bodies of water with a K+/Na+ ratio necessary to sustain life. In this conditions sodium pump is not needed and the pump can originate later. But why the pump is needed if K+/Na+ ratio is good? The origin of the sodium pump in conditions where there is no natural need for it may require the agency of Providence.
I have previously thought of the cell membrane as a means to preserve an environment where the replicating molecules survive and thus make them more viable than the molecules alone.
In the above scenario we could have evaporating ponds providing the concentrations, then the cell membranes to protect them, perhaps in a semi-dormant phase, and then the pump.
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RAZD: "In the above scenario we could have evaporating ponds providing the concentrations, then the cell membranes to protect them, perhaps in a semi-dormant phase, and then the pump." Matveev: Only one question: why membrane sodium pump is needed in the potassium pond? In the pond K+/Na+ ratio is the same as in the living cell.
If you'd used the quote codes your message would have looked like this:
RAZD writes:
In the above scenario we could have evaporating ponds providing the concentrations, then the cell membranes to protect them, perhaps in a semi-dormant phase, and then the pump.
Only one question: why membrane sodium pump is needed in the potassium pond? In the pond K+/Na+ ratio is the same as in the living cell.
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why membrane sodium pump is needed in the potassium pond? In the pond K+/Na+ ratio is the same as in the living cell.
First, evolution does not work with a purpose. Is there some reason such a pump, even a most primitive one, could not develop absent a need? Second, does the ratio remain the same forever?
Only one question: why membrane sodium pump is needed in the potassium pond? In the pond K+/Na+ ratio is the same as in the living cell.
To contain the concentration when the pond is diluted (rains) and perhaps they get flushed out of the pond into a stream etc. So the proto-life is now capable of surviving drought with the membrane and flood with the pump.
It is surviving to reproduce, it is evolving. I see "life" beginning when evolution begins - beneficial traits are passed down from generation to generation.
quote:First, evolution does not work with a purpose. Is there some reason such a pump, even a most primitive one, could not develop absent a need? Second, does the ratio remain the same forever?
Sea tide floods potassium pond. And what happens after that?
quote:To contain the concentration when the pond is diluted (rains) and perhaps they get flushed out of the pond into a stream etc. So the proto-life is now capable of surviving drought with the membrane and flood with the pump.
We need physical mechanisms rather than general assumptions. Pump, pump, pump... Where is experimental evidence of its spontaneous origin? There is no evidences, no proofs! No pump, no life.
We need physical mechanisms rather than general assumptions. Pump, pump, pump... Where is experimental evidence of its spontaneous origin? There is no evidences, no proofs! No pump, no life.
For the sake of discussion let's say that there's no pump, and that that means there's no life. But obviously there's life, so what does the absence of a sodium pump mean to you?
quote:First, evolution does not work with a purpose. Is there some reason such a pump, even a most primitive one, could not develop absent a need? Second, does the ratio remain the same forever?
That was AZPaul3 in Message 9. The correct [reply] button is at the bottom of a post rather than at the top.
Indeed, I like to think of it as a series of accidents, some happy some not so happy.
Sea tide floods potassium pond. And what happens after that?
For the proto-life without a pump it has a problem maintaining it's optimum inner ecology, and osmosis would not help.
Thus an "accident" that provided a pumping action would be beneficial, allowing it to survive and breed in the wider environment.
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