To understand why random events are not a good explanation, we best have a look at the deepest level, on an atomic scale. Life uses just five nucleobases to make DNA and RNA. Two purines, and three pyrimidines. Purines use two rings with nine atoms, pyrimidines use just one ring with six atoms. Hydrogen bonding between purine and pyrimidine bases is fundamental to the biological functions of nucleic acids, as in the formation of the double-helix structure of DNA. This bonding depends on the selection of the right atoms in the ring structure. Pyrimidine rings consist of six atoms: 4 carbon atoms and 2 nitrogen atoms. Purines have nine atoms forming the ring: 5 carbon atoms and 4 nitrogen atoms.
Remarkably, it is the composition of these atoms that permit that the strength of the hydrogen bond that permits to join the two DNA strands and form Watson–Crick base-pairing, and well-known DNA ladder. Neither transcription nor translation of the messages encoded in RNA and DNA would be possible if the strength of the bonds had different values. Hence, life, as we understand it today, would not have arisen.
Now, someone could say, that there could be no different composition, and physical constraints and necessity could eventually permit only this specific order and arrangement of the atoms. Now, in a recent science paper from 2019, Scientists explored how many different chemical arrangements of the atoms to make these nucleobases would be possible. Surprisingly, they found well over a million variants. The remarkable thing is, among the incredible variety of organisms on Earth, these two molecules are essentially the only ones used in life. Why? Are these the only nucleotides that could perform the function of information storage? If not, are they perhaps the best? One might expect that molecules with smaller connected Carbon components should be easier for abiotic chemistry to explore.
According to their scientific analysis, the natural ribosides and deoxyribosides inhabit a fairly redundant ( in other words, superfluous, unnecessary, needless, and nonminimal region of this space. This is a remarkable find and implicitly leads to design. There would be no reason why random events would generate complex, rather than simple, and minimal carbon arrangements. Nor is there physical necessity that says that the composition should be so. This is evidence that a directing intelligent agency is the most plausible explanation. The chemistry space is far too vast to select by chance the right finely-tuned functional life-bearing arrangement.
In the mentioned paper, the investigators asked if other, perhaps equally good, or even better genetic systems would be possible. Their chemical experimentations and studies concluded that the answer is no. Many nearly as good, some equally good, and a few stronger base-pairing analog systems are known. There is no reason why these structures could or would have emerged in this functional complex configuration by random trial and error. There is a complete lack of scientific-materialistic explanations despite decades of attempts to solve the riddle.
What we can see is, that direct intervention, a creative force, the activity of an intelligent agency, a powerful creator, is capable to have the intention and implement the right arrangement of every single atom into functional structures and molecules in a repetitive manner, in the case of DNA, at least 500 thousand nucleotides to store the information to kick-start life, exclusively with four bases, to produce a storage device that uses a genetic code, to store functional, instructional, complex information, functional amino acids, and phospholipids to make membranes, and ultimately, life. Lucky accidents, the spontaneous self-organization by unguided coincidental events, that drove atoms into self-organization in an orderly manner without external direction, chemical non-biological are incapable and unspecific to arrange atoms into the right order to produce the four classes of building blocks, used in all life forms.
2. Jeffrey Bada, develoment of amino acids, nitrides, carbon dioxide,
3. iron, the problem of import of iron into the cell
4. Self replication or RNA
5. There was no prebiotic selection or nucleotides
The very origin of the first organisms presents at least an appearance of a paradox because a certain minimum level of complexity is required to make self-replication possible at all; high-fidelity replication requires additional functionalities that need even more information to be encoded. The crucial question is how the Darwin-Eigen cycle could have started—how was the minimum complexity that is required to achieve the minimally acceptable replication fidelity attained? In even the simplest modern systems, such as RNA viruses, replication is catalyzed by complex protein polymerases. The replicase itself is produced by translation of the respective mRNA(s), which is mediated by the immensely complex ribosomal apparatus. Hence, the dramatic paradox of the origin of life is that to attain the minimum complexity required for a biological system to start on the Darwin-Eigen spiral, a system of a far greater complexity appears to be required. How such a system could emerge is a puzzle that defeats conventional evolutionary thinking, all of which is about biological systems moving along the spiral; the solution is bound to be unusual. The origin of life—or, to be more precise, the origin of the first replicator systems and the origin of translation—remains a huge enigma, and progress in solving these problems has been very modest—in the case of translation, nearly negligible.4
6. protocells, fatty acids
a lipid membrane would be useless without membrane proteins but how could membrane proteins have evolved in the absence of functional membranes?
Prebiotic cell membrane synthesis
How could simple amphiphiles, which are molecules containing a nonpolar hydrophobic region and a polar hydrophilic region will self-assemble in aqueous solutions to form distinct structures such as micelles have been available in the prebiotic inventory if there has never been evidence for this? Furthermore, sources of compounds with hydrocarbon chains sufficiently long to form stable membranes are not known.
How could prebiotic mechanisms have transported and concentrated organic compounds to the pools and construction site?
How could membranous vesicles have self-assembled to form complex mixtures of organic compounds and ionic solutes, if science has no solution to this question?
How could there have been a prebiotic route of lipid compositions that could provide a membrane barrier sufficient to maintain proton gradients? Proton gradients are absolutely necessary for the generation of energy.
How to explain that lipid membranes would be useless without membrane proteins but how could membrane proteins have emerged or evolved in the absence of functional membranes?
How did prebiotic processes select hydrocarbon chains which must be in the range of 14 to 18 carbons in length? There was no physical necessity to form carbon chains of the right length nor hindrance to join chains of varying lengths. So they could have been existing of any size on the early earth.
How could there have been an "urge" for prebiotic compounds to add unsaturated cis double bonds near the center of the chain?
How is there a feasible route of prebiotic phospholipid synthesis, to the complex metabolic phospholipid and fatty acid synthesis pathways performed by multiple enzyme-catalyzed steps which had to be fully operational at LUCA?
How would random events start to attach two fatty acids to glycerol by ester or ether bonds rather than just one, necessary for the cell membrane stability?
How would random events start to produce biological membranes which are not composed of pure phospholipids, but instead are mixtures of several phospholipid species, often with a sterol admixture such as cholesterol? There is no feasible prebiotic mechanism to join the right mixtures.
How did unguided events produce the essential characteristic of living cells which is homeostasis, the ability to maintain a steady and more-or-less constant chemical balance in a changing environment? The first forms of life required an effective Ca2+ homeostatic system, which maintained intracellular Ca2+ at comfortably low concentrations—somewhere ∼10,000–20,000 times lower than that in the extracellular milieu. There was no mechanism to generate this gradient.
How was the transition generated from supposedly simple vesicles on the early earth to the ultracomplex membrane synthesis in modern cells, which would have to be extant in the last universal common ancestor, hosting at least over 70 enzymes?
Finetuning of the electromagnetic forces
Fine-tuning of the electromagnetic forces, evidence of design?
Last edited by Otangelo on Wed Nov 18, 2020 3:05 pm; edited 3 times in total (Reason for editing : a lipid membrane would be useless without membrane proteins but how could membrane proteins have evolved in the absence of functional membranes?)