Theoretical origin of life: more ruminations (Introduction)

by David Turell @, Saturday, November 28, 2015, 00:31 (3044 days ago) @ David Turell

This article wonders whether the environment when lie began on Earth was so different from now that it creates a problem of duplicating conditions. We do know how to make all the molecules under specific lab conditions, but putting them together organized as life is totally beyond us at this point.:-https://theconversation.com/imagining-strange-new-lifeforms-could-help-us-discover-our-own-origins-44869-But how did the very first cells emerge? Living systems are chemically based and therefore must obey the laws of science. Life appears to be just a series of chemical reactions - and we now understand how these reactions work at the molecular level. So surely this should tell us how life came about?-***-The real problem is in understanding how this “machinery” of chemicals came together to generate life. The watershed where lifeless chemical activity is transformed into organised biological metabolism is extremely difficult to identify and the trigger for this is a key ingredient missing from the “primordial soup”.-The assumption that early life forms must have been similar to what we see today may be preventing us from answering this question. It's possible that there were many unsuccessful precursors that bore little resemblance to present-day life. There has been speculation that primitive starting points could even have been based around an element other than carbon (the substance at the heart of all life today). Some researchers suggest that life may have originally evolved in liquids other than water. These alternatives are fascinating, but it's difficult to find a starting point for researching them because they are so unfamiliar.-A key trait that sets life apart from inanimate matter is its reliance on organisation. Molecules must be arranged in a specific way and replicate according to a detailed pattern. But the natural tendency of the whole universe is towards a state of equilibrium, or balance - where everything is spread out and nothing is ordered. Maintaining an ordered structure means life is constantly off-balance and this requires energy, which organisms must extract from their surroundings.-One way that organisms do this it to cause movement of molecules or even sub-atomic particles that can then generate energy for a cell. For example, organisms living in hydrothermal vents on the sea floor get their energy from the transfer of protons through the cell membrane.
Living systems maintain their “off-balance” state by combining the ability to self-replicate with the ability to extract energy from their surroundings. To discover the origin of life, we need to understand how these properties combined to form a sustainable unit.-Some scientists are adopting a top-down approach, attempting to answer this question by removing bits of a living cell to determine the minimum structure required to sustain life. Others are approaching it from the bottom-up by combining the building blocks in a primitive container to mimic a simple cell.-While both approaches may be enlightening, the precise moment of transition from chemical to life (and vice versa) still evades us. But the lack of discovery is fascinating in itself - it confirms that creating life is difficult and requires conditions that are no longer naturally present on the Earth. A breakthrough in this area would not only tell us the requirements for life, but also the circumstances of its emergence.-Comment: No mention of information. Without it how are all those molecules organized?


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