scholarly journals An optimal degree of physical and chemical heterogeneity for the origin of life?

2011 ◽  
Vol 366 (1580) ◽  
pp. 2894-2901 ◽  
Author(s):  
Jack W. Szostak
Keyword(s):  
Nucleic Acid ◽  
Origin Of Life ◽  
Self Assembly ◽  
Building Blocks ◽  
Reaction Products ◽  
Amphiphilic Molecules ◽  
Essential Components ◽  
The Origin Of Life ◽  
Chemical Inputs ◽  
Physical And Chemical

The accumulation of pure, concentrated chemical building blocks, from which the essential components of protocells could be assembled, has long been viewed as a necessary, but extremely difficult step on the pathway to the origin of life. However, recent experiments have shown that moderately increasing the complexity of a set of chemical inputs can in some cases lead to a dramatic simplification of the resulting reaction products. Similarly, model protocell membranes composed of certain mixtures of amphiphilic molecules have superior physical properties than membranes composed of single amphiphiles. Moreover, membrane self-assembly under simple and natural conditions gives rise to heterogeneous mixtures of large multi-lamellar vesicles, which are predisposed to a robust pathway of growth and division that simpler and more homogeneous small unilamellar vesicles cannot undergo. Might a similar relaxation of the constraints on building block purity and homogeneity actually facilitate the difficult process of nucleic acid replication? Several arguments suggest that mixtures of monomers and short oligonucleotides may enable the chemical copying of polynucleotides of sufficient length and sequence complexity to allow for the emergence of the first nucleic acid catalysts. The question of the origin of life may become less daunting once the constraints of overly well-defined laboratory experiments are appropriately relaxed.

Photochemical Evolution of Interstellar/Precometary Organic Material

1997 ◽  
Vol 161 ◽  
pp. 23-47 ◽  
Author(s):  
Louis J. Allamandola ◽  
Max P. Bernstein ◽  
Scott A. Sandford
Keyword(s):  
Origin Of Life ◽  
Building Blocks ◽  
Complex Species ◽  
Infrared Observations ◽  
Interstellar Ice ◽  
Polycyclic Aromatic ◽  
Ultraviolet Photolysis ◽  
The Origin Of Life ◽  
Simple Molecules ◽  
Complex Organic

AbstractInfrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Since comets are thought to be a major source of the volatiles on the primative earth, their organic inventory is of central importance to questions concerning the origin of life. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, CH4, H2, and probably some NH3and H2CO, as well as more complex species including nitriles, ketones, and esters. The evidence for these, as well as carbonrich materials such as polycyclic aromatic hydrocarbons (PAHs), microdiamonds, and amorphous carbon is briefly reviewed. This is followed by a detailed summary of interstellar/precometary ice photochemical evolution based on laboratory studies of realistic polar ice analogs. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(= O)NH2(formamide), CH3C(= O)NH2(acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including polyoxymethylene and related species (POMs), amides, and ketones. The ready formation of these organic species from simple starting mixtures, the ice chemistry that ensues when these ices are mildly warmed, plus the observation that the more complex refractory photoproducts show lipid-like behavior and readily self organize into droplets upon exposure to liquid water suggest that comets may have played an important role in the origin of life.

General discussion after session V

1988 ◽  
Vol 325 (1587) ◽  
pp. 611-618 ◽  
Keyword(s):  
Origin Of Life ◽  
Time Perspective ◽  
Applied Mathematics ◽  
Building Blocks ◽  
Living Systems ◽  
Organic Chemical ◽  
General Terms ◽  
The Earth ◽  
The Origin Of Life ◽  
Emergence Of Life

N. C. Wickramasinghe ( Department of Applied Mathematics and Astronomy, University College, Cardiff, U. K. ). The question of the origin of life is, of course, one of the most important scientific questions and it is also one of the most difficult. One is inevitably faced here with a situation where there are very few empirical facts of direct relevance and perhaps no facts relating to the actual transition from organic material to material that can even remotely be described as living. The time perspective of events that relate to this problem has already been presented by Dr Chang. Uncertainty still persists as to the actual first moment of the origin or the emergence of life on the Earth. At some time between 3800 and 3300 Ma BP the first microscopic living systems seem to have emerged. There is a definite moment in time corresponding to a sudden appearance of cellular-type living systems. Now, traditionally the evolution of carbonaceous compounds which led to the emergence of life on Earth could be divided into three principal steps and I shall just remind you what those steps are. The first step is the production of chemical building blocks that lead to the origin of the organic molecules necessary as a prerequisite for the evolution of life. Step two can be described in general terms as prebiotic evolution, the arrangement of these chemical units into some kind of sequence of precursor systems that come almost up to life but not quite; and then stage three is the early biological evolution which actually effects the transition from proto-cellular organic-type forms into truly cellular living systems. The transition is from organic chemistry, prebiotic chemistry to biochemistry. Those are the three principal stages that have been defined by traditional workers in the field, the people who, as Dr Chang said, have had the courage to make these queries and attempt to answer them. Ever since the classic experiments where organic materials were synthesized in the laboratory a few decades back, it was thought that the first step, the production of organic chemical units, is important for the origin of life on the Earth, and that this had to take place in some location on the Earth itself.

How Did It All Begin?: The Self-Assembly of Organic Molecules and the Origin of Cellular Life

2002 ◽  
Vol 11 ◽  
pp. 179-194
Author(s):  
David W. Deamer
Keyword(s):  
Origin Of Life ◽  
20Th Century ◽  
Self Assembly ◽  
Organic Molecules ◽  
Western Culture ◽  
The Self ◽  
Late 20Th Century ◽  
Cellular Life ◽  
The Earth ◽  
The Origin Of Life

Movies are the myths of late-20th century western culture. Because of the power of films likeETto capture our imagination, we are more likely than past generations to accept the possibility that life exists elsewhere in our galaxy. Such a myth can be used to sketch the main themes of this chapter, which concern the origin of life on the Earth.

scholarly journals Differential adsorption of nucleic acid bases: Relevance to the origin of life

2001 ◽  
Vol 98 (3) ◽  
pp. 820-822 ◽  
Author(s):  
S. J. Sowerby ◽  
C. A. Cohn ◽  
W. M. Heckl ◽  
N. G. Holm
Keyword(s):  
Nucleic Acid ◽  
Origin Of Life ◽  
Nucleic Acid Bases ◽  
The Origin Of Life

Proliferating droplets formed via prebiotic polymerisation: the missing link between chemistry and biology on the origin of life

2020 ◽  
Author(s):  
Muneyuki Matsuo ◽  
Kensuke Kurihara
Keyword(s):  
Phase Separation ◽  
Origin Of Life ◽  
Self Assembly ◽  
Primitive Cell ◽  
Material Development ◽  
Steady Growth ◽  
Prebiotic Molecules ◽  
The Origin Of Life ◽  
Acid Thioesters ◽  
Liquid Liquid Phase Separation

Abstract The hypothesis that prebiotic molecules were transformed into polymers that evolved into proliferating molecular assemblages and eventually a primitive cell was first proposed about a hundred years ago. However, no proliferating model prebiotic system has yet been realised because different conditions are required for polymer generation and self-assembly of polymers. In this study, we identified conditions suitable for concurrent peptide generation and self-assembly, and we showed how a proliferating peptide-based droplet could be created by using synthesised amino acid thioesters as prebiotic monomers. Oligopeptides generated from the monomers spontaneously formed droplets through liquid–liquid phase separation in water. The droplets underwent a steady growth–division cycle by periodic addition of monomers through autocatalytic self-reproduction. Heterogeneous enrichment of RNA and lipids within droplets enabled RNA to protect the droplet from dissolution by lipids. These results provide experimental platforms for origin-of-life research and open up novel directions in peptide-based material development.

Protective effect of clay minerals on adsorbed nucleic acid against UV radiation: possible role in the origin of life

2004 ◽  
Vol 3 (1) ◽  
pp. 17-19 ◽  
Author(s):  
F. Scappini ◽  
F. Casadei ◽  
R. Zamboni ◽  
M. Franchi ◽  
E. Gallori ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Protective Effect ◽  
Origin Of Life ◽  
Clay Minerals ◽  
Uv Radiation ◽  
Laboratory Experiments ◽  
Biological Evolution ◽  
The Earth ◽  
The Origin Of Life ◽  
Uv Photons

The effect of UV radiation on solutions of free and clay-adsorbed DNA has been investigated. It turns out that clay (montmorillonite/kaolinite) adsorbed nucleic acid undergoes less radiation damage than free nucleic acid. Our laboratory experiments have an astronomical counterpart in terms of solar irradiance on the Earth. An origin of life scenario is proposed where ubiquitous clay minerals lead the surface chemistry of the molecules relevant to the biological evolution and at the same time protect them from the deadly rainfall of UV photons.

scholarly journals Search for water and life's building blocks in the universe: A summary

2015 ◽  
Vol 11 (A29B) ◽  
pp. 436-440
Author(s):  
Edwin A. Bergin
Keyword(s):  
Origin Of Life ◽  
Radioactive Decay ◽  
Building Blocks ◽  
The Origin Of Life ◽  
The Right ◽  
The Universe

AbstractWater and organics need to be supplied to terrestrial worlds like our own to provide the essential compounds required for the origin of life. These molecules form initially during the earliest stages of stellar birth, are supplied by collapse to the planet-forming disk predominantly as ice, and may undergo significant processing during this collapse and within large planetesimals that are heated via radioactive decay. Water and organic carriers can be quite volatile, thus their survival as ices within rocks is not preordained. In this focus meeting our goal is to bring together astronomers, cosmochemists, planetary scientists, chemical physicists, and spectroscopists who each explore individual aspects of this problem. In this summary we discuss some of the main themes that appeared in the meeting. Ultimately, cross-field collaboration is needed to provide greater understanding of the likelihood that terrestrial worlds form with these key compounds readily available on their surfaces – and are hence habitable if present at the right distance from the star.

The first step from molecules to life: Formation of large random molecules acting as micro-environments

2020 ◽  
Author(s):  
Saibal Mitra
Keyword(s):  
Molecular Biology ◽  
Origin Of Life ◽  
Ultraviolet Irradiation ◽  
Building Blocks ◽  
Percolation Process ◽  
Von Neumann ◽  
Percolation Clusters ◽  
Period 2 ◽  
Interstellar Ice ◽  
The Origin Of Life

<p>The mathematician John von Neumann, through his work on universal constructors, discovered<br />a generalized version of the central dogma of molecular biology biology in the 1940s, long  <br />before the biological version had been discovered. While his discovery played no role in the  <br />development of molecular biology, we may benefit from a similar mathematical approach to find  <br />clues on the origin of life. This then involves addressing those problems in the field that  <br />do not depend on the details of organic chemistry. We can then consider a general set of  <br />models that describe machines capable of self-maintenance and self-replication formulated in  <br />terms of a set of building blocks and their interactions. </p> <p>The analogue of the origin of life problem is then to explain how one can get to such  <br />machines starting from a set of only building blocks. A fundamental obstacle one then faces  <br />is the limit on the complexity of low fidelity replicating systems, preventing building  <br />blocks from getting assembled randomly into low fidelity machines which can then improve due  <br />to natural selection [1]. A generic way out of this problem is for the entire ecosystem of  <br />machines to have been encapsulated in a micro-structure with fixed inner surface features  <br />that would have boosted the fidelity [2]. Such micro-structures could have formed as a result  <br />of the random assembly of building blocks, leading to so-called percolation clusters [2].</p> <p>This then leads us to consider how in the real world a percolation process involving the  <br />random assembly of organic molecules can be realized. A well studied process in the  <br />literature is the assembly of organic compounds in ice grains due to UV radiation and heating  <br />events [3,4,5]. This same process will also lead to the percolation process if it proceeds  <br />for a sufficiently long period [2].</p> <p>In this talk I will discuss the percolation process in more detail than has been done in [2],  <br />explaining how it leads to the necessary symmetry breakings such as the origin of chiral  <br />molecules needed to explain the origin of life.   </p> <p> </p> <p>[1] Eigen, M., 1971. Self-organization of matter and the evolution of biological  <br />macromolecules. Naturwissenschaften 58, 465-523.</p> <p>[2] Mitra, S., 2019. Percolation clusters of organics in interstellar ice grains as the  <br />incubators of life, Progress in Biophysics and Molecular Biology 149, 33-38.</p> <p>[3] Ciesla, F., and Sandford.,S., 2012. Organic Synthesis via Irradiation and Warming of Ice  <br />Grains in the Solar Nebula. Science 336, 452-454.</p> <p>[4] Muñoz Caro, G., et al., 2002. Amino acids from ultraviolet irradiation of interstellar ice  <br />analogues. Nature 416, 403-406.</p> <p>[5]  Meinert, C,., et al., 2016. Ribose and related sugars from ultraviolet irradiation of  <br />interstellar ice analogs. Science 352, 208-212.</p>

Sign in / Sign up

Export Citation Format

Share Document