DOCSLIB.ORG

Planetary Organic Chemistry and the Origins of Biomolecules

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Planetary Organic Chemistry and the Origins of Biomolecules Downloaded from http://cshperspectives.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press Planetary Organic Chemistry and the Origins of Biomolecules Steven A. Benner, Hyo-Joong Kim, Myung-Jung Kim, and Alonso Ricardo Foundation for Applied Molecular Evolution and The Westheimer Institute for Science and Technology, Gainesville, Florida 32601 Correspondence: [email protected] Organic chemistry on a planetary scale is likely to have transformed carbon dioxide and reduced carbon species delivered to an accreting Earth. According to various models for the origin of life on Earth, biological molecules that jump-started Darwinian evolution arose via this planetary chemistry. The grandest of these models assumes that ribonucleic acid (RNA) arose prebiotically, together with components for compartments that held it and a primitive metabolism that nourished it. Unfortunately, it has been challenging to iden- tify possible prebiotic chemistry that might have created RNA. Organic molecules, given energy, have a well-known propensity to form multiple products, sometimes referred to col- lectively as “tar” or “tholin.” These mixtures appear to be unsuited to support Darwinian processes, and certainly have never been observed to spontaneously yield a homochiral genetic polymer. To date, proposed solutions to this challenge either involve too much direct human intervention to satisfy many in the community, or generate molecules that are unreactive “dead ends” under standard conditions of temperature and pressure. Carbohydrates, organic species having carbon, hydrogen, and oxygen atoms in a ratio of 1:2:1 and an aldehyde or ketone group, conspicuously embody this challenge. Theyare com- ponents of RNA and their reactivity can support both interesting spontaneous chemistry as part of a “carbohydrate world,” but they also easily form mixtures, polymers and tars. We describe here the latest thoughts on how on this challenge, focusing on how it might be resolved using minerals containing borate, silicate, and molybdate, inter alia. nteresting organic chemistry occurs through- certainly contributed to the reduced carbon Iout the cosmos, including in presolar nebulae inventory on Earth before life emerged, plane- (see the article in this collection by Pascale Erh- tary processing on Earth undoubtedly also con- renfreund), asteroidal bodies (see the article in tributed to the inventory of prebiotic molecules this collection by Sandra Pizzarello) and icy that were available to life as it originated (as- bodies near the outer boundary of our solar sys- suming that Earth was the site of life’s origin). tem (Bernstein et al. 2002). Although organic Indeed, in the RNA first model for the origin molecules made in off-Earth locales almost of life on Earth (Joyce and Orgel 1999)(Benner Editors: David Deamer and Jack W. Szostak Additional Perspectives on The Origins of Life available at www.cshperspectives.org Copyright # 2010 Cold Spring Harbor Laboratory Press; all rights reserved. Advanced Online Article. Cite this article as Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a003467 1 Downloaded from http://cshperspectives.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press S.A. Benner et al. 2009), it is often proposed that terran-based organic transformations might have occurred on chemistry produced RNA in oligomeric form dry land or below water on a planetary surface to initiate Darwinian evolution. that was totally submerged. How are we to constrain models for planetary processing to converge on a model for what actually happened on Earth four billion years BACKGROUND ago? Today, atmospheric dioxygen (O2)readily Organic Molecules with Energy converts organic materials to carbon dioxide, Spontaneously Yield Polymers and Complex making it essentially impossible to observe such Mixtures processing on the surface of Earth. Furthermore, the ubiquity of life on modern Earth means that Any model for planetary organic chemistry must any organic processing is more likely to reflect recognize that very few organic molecules are biology than prebiology. The closest we may thermodynamically stable in water, either with come today to observe organic transformations respect to conversion to their fully hydrated state absent biology on a planetary scale might be on or decomposition upon heating to elemental car- Titan, a moon of Saturn whose atmosphere and bon (charcoal), carbon dioxide, orother thermo- surface is rich in reduced carbon. dynamic “end points.” Accordingly, any model Nevertheless, it is possible to apply a general for planetary prebiotic chemistry must address understanding of organic chemical reactivity to the metastability of organic species. This word suggest chemical reactions that might have captures the concept that organic molecules that occurred on early Earth and the products that have appeared through the interaction of precur- they might have produced. These suggestions sors with energy, water, and other organics can are constrained by models for the atmosphere then disappear upon further interaction. As and mineralogy of early Earth, although these many authors have noted (Cairns-Smith 1982; constraints might change as models improve. Shapiro 1987; Shapiro 2007), any prebiotic reac- In this article, we assume that the atmos- tion scheme that requires two or more organic phere of early Earth was less oxidizing than species must be concerned about the metastabil- today’s atmosphere, although not as rich in ity of two or more species; any scheme that does methane as the simulated atmosphere used in not produce both components in useful concen- the classic experiments of Stanley Miller (Miller trations at the same time will not meet a standard 1955). Further, we assume that the atmosphere of proof that the community need to accept a on early Earth had access to many sources solution to the problem. of energy. These include electrical discharge, Here, too, the mineral inventory of early ultraviolet and visible light (although the Sun Earthcannotbeignored.Mineralsofmanykinds was almost certainly dimmer then than now, a may have guided the reactivityof organic species Titan-like haze may have prevented high energy that emerged on early Earth, altered their meta- photons from reacting the Earth’s surface), stability, and influenced the time when specific volcanism (providing not only heat but also organic species were available to emerging life. reactive species and mixtures not at thermo- dynamic equilibrium), ionizing radiation, and Carbohydrates Embody this Natural impacts.(SeePizzarelloandShock2010foradis- Propensity to Polymerize cussion of such energy sources.) We also assume that life emerged after Toexplorethese points anddevelop the scientific the planet underwent a geological fractionation methods that enable this exploration, we will use in which heavier minerals and elemental iron carbohydrates as a focus. Carbohydrates are sank towards the core, leaving lighter rocks to organic species having carbon, hydrogen and formthecrust.Openquestionsconcerntheinven- oxygen atoms in a ratio of 1:2:1. They are there- tory of water relative to the surface of early Earth, fore at the same oxidation level of elemental car- an inventory that determined whether planetary bon. Furthermore the simplest carbohydrate, 2 Advanced Online Article. Cite this article as Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a003467 Downloaded from http://cshperspectives.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press Planetary Organic Chemistry and the Origins of Biomolecules formaldehyde (HCHO, H2C¼O, or C1H2O1)is and preclude certain compound classes based easily generated by electrical discharge or ultra- on the same data, characterizes the “origins” field violet radiation impinging on moist atmos- in general (Benner 2009). To evaluate such con- pheres that are rich in carbon dioxide; nearly tradicting views, participants in this field must every contemporary model for early Earth per- understand relevant features of bonding and mitssuchatmospheres(Pintoetal.1980;Cleaves reactivity in organic molecules. This understand- 2008).Becausetheycontainketoneandaldehyde ing requires in turn that they understand the for- groups (see later), carbohydrates have interest- malisms used by organic chemists to describe ing reactivity that includes the ability to form bonding and reactivity in organic molecules. newcarbon-carbonbondsunder “standardcon- Although the features and formalisms are taught ditions,” defined as those where water is liquid in introductory organic chemistry courses, it is under contemporary terran atmospheric pres- worth summarizing them here a prelude to dis- sure. By comparison, the compounds that often cussing constraints on reactions that might be concern prebiotic chemists (carboxylic acids, expected to occur in prebiotic environments. fatty acids, and amino acids, for example) have First, a single bond joining two carbon essentially no such reactivity. Indeed, carbohy- atoms is strong, on the order of 400 kJ (100 drates are “high energy” because they can rear- kcal) per mole. This means that a pair of carbon range their constituent atoms to give carboxylic atoms joined by a typical single bond will acid derivatives and other more stable end point remain joined for many millions of years at tem- “sinks.” peratures when water is a liquid at sea level on Recognizing this, some authors, most nota- Earth near neutral pH (“standard conditions”).
Load more

Recommended publications
  • Modelling Panspermia in the TRAPPIST-1 System
    October 13, 2017 Modelling panspermia in the TRAPPIST-1 system James A. Blake1,2*, David J. Armstrong1,2, Dimitri Veras1,2 Abstract The recent ground-breaking discovery of seven temperate planets within the TRAPPIST-1 system has been hailed as a milestone in the development of exoplanetary science. Centred on an ultra-cool dwarf star, the planets all orbit within a sixth of the distance from Mercury to the Sun. This remarkably compact nature makes the system an ideal testbed for the modelling of rapid lithopanspermia, the idea that micro-organisms can be distributed throughout the Universe via fragments of rock ejected during a meteoric impact event. We perform N-body simulations to investigate the timescale and success-rate of lithopanspermia within TRAPPIST-1. In each simulation, test particles are ejected from one of the three planets thought to lie within the so-called ‘habitable zone’ of the star into a range of allowed orbits, constrained by the ejection velocity and coplanarity of the case in question. The irradiance received by the test particles is tracked throughout the simulation, allowing the overall radiant exposure to be calculated for each one at the close of its journey. A simultaneous in-depth review of space microbiological literature has enabled inferences to be made regarding the potential survivability of lithopanspermia in compact exoplanetary systems. 1Department of Physics, University of Warwick, Coventry, CV4 7AL 2Centre for Exoplanets and Habitability, University of Warwick, Coventry, CV4 7AL *Corresponding author: [email protected] Contents Universe, and can propagate from one location to another. This interpretation owes itself predominantly to the works of William 1 Introduction1 Thompson (Lord Kelvin) and Hermann von Helmholtz in the 1.1 Mechanisms for panspermia...............2 latter half of the 19th Century.
    [Show full text]
  • Prebiological Evolution and the Metabolic Origins of Life
    Prebiological Evolution and the Andrew J. Pratt* Metabolic Origins of Life University of Canterbury Keywords Abiogenesis, origin of life, metabolism, hydrothermal, iron Abstract The chemoton model of cells posits three subsystems: metabolism, compartmentalization, and information. A specific model for the prebiological evolution of a reproducing system with rudimentary versions of these three interdependent subsystems is presented. This is based on the initial emergence and reproduction of autocatalytic networks in hydrothermal microcompartments containing iron sulfide. The driving force for life was catalysis of the dissipation of the intrinsic redox gradient of the planet. The codependence of life on iron and phosphate provides chemical constraints on the ordering of prebiological evolution. The initial protometabolism was based on positive feedback loops associated with in situ carbon fixation in which the initial protometabolites modified the catalytic capacity and mobility of metal-based catalysts, especially iron-sulfur centers. A number of selection mechanisms, including catalytic efficiency and specificity, hydrolytic stability, and selective solubilization, are proposed as key determinants for autocatalytic reproduction exploited in protometabolic evolution. This evolutionary process led from autocatalytic networks within preexisting compartments to discrete, reproducing, mobile vesicular protocells with the capacity to use soluble sugar phosphates and hence the opportunity to develop nucleic acids. Fidelity of information transfer in the reproduction of these increasingly complex autocatalytic networks is a key selection pressure in prebiological evolution that eventually leads to the selection of nucleic acids as a digital information subsystem and hence the emergence of fully functional chemotons capable of Darwinian evolution. 1 Introduction: Chemoton Subsystems and Evolutionary Pathways Living cells are autocatalytic entities that harness redox energy via the selective catalysis of biochemical transformations.
    [Show full text]
  • Chemical Evolution Theory of Life's Origins the Lattimer, AST 248, Lecture 13 – P.2/20 Organics
    Chemical Evolution Theory of Life's Origins 1. the synthesis and accumulation of small organic molecules, or monomers, such as amino acids and nucleotides. • Production of glycine (an amino acid) energy 3HCN+2H2O −→ C2H5O2N+CN2H2. • Production of adenine (a base): 5 HCN → C5H5N5, • Production of ribose (a sugar): 5H2CO → C5H10O5. 2. the joining of these monomers into polymers, including proteins and nucleic acids. Bernal showed that clay-like materials could serve as sites for polymerization. 3. the concentration of these molecules into droplets, called protobionts, that had chemical characteristics different from their surroundings. This relies heavily on the formation of a semi-permeable membrane, one that allows only certain materials to flow one way or the other through it. Droplet formation requires a liquid with a large surface tension, such as water. Membrane formation naturally occurs if phospholipids are present. 4. The origin of heredity, or a means of relatively error-free reproduction. It is widely, but not universally, believed that RNA-like molecules were the first self-replicators — the RNA world hypothesis. They may have been preceded by inorganic self-replicators. Lattimer, AST 248, Lecture 13 – p.1/20 Acquisition of Organic Material and Water • In the standard model of the formatio of the solar system, volatile materials are concentrated in the outer solar system. Although there is as much carbon as nearly all other heavy elements combined in the Sun and the bulk of the solar nebula, the high temperatures in the inner solar system have lead to fractional amounts of C of 10−3 of the average.
    [Show full text]
  • Nomination Background: Dihydroxyacetone (CASRN: 96-26-4)
    SUMMARY OF DATA FOR CHEMICAL SELECTION Dihydroxyacetone 96-26-4 BASIS OF NOMINATION TO THE CSWG As consumers have become more mindful of the hazards ofa "healthy tan," more individuals have turned to sunless tanning. Sunless tanning products represent about 10% of the $400 million market for suntan preparations, and these products are the fastest growing segment of the suntanning preparation market. All sunless tanners contain dihydroxyacetone. Information on the toxicity of dihydroxyacetone appears contradictory. A mutagen that induces DNA strand breaks, dihydroxyacetone is also an intermediate in carbohydrate metabolism in higher plants and animals. Such contradictions are not unprecedented, and it has been suggested that autooxidation of cx-hydroxycarbonyl compounds including reducing sugars may play a role in diseases associated with age and diabetes (Morita, 1991 ). When dihydroxyacetone was applied to the skin of mice, no carcinogenic effect was observed. It is unclear whether this negative response was caused by a failure ofthe compound to penetrate the skin. If so, extrapolating the dermal results to other routes of exposure would not be appropriate. NCI is nominating dihydroxyacetone to the NTP for dermal penetration studies in rats and mice to determine whether dihydroxyacetone can penetrate the skin. This information will clarify whether additional testing of dihydroxyacetone is warranted. Dihydroxyacetone 96-26-4 CHEMICAL IDENTIFICATION CAS Registry Number: 96-26-4 Chemical Abstracts Service Name: 1,3-Dihydroxy-2-propanone (9CI; 8CI) Synonyms and Tradenames: 1,3-Dihydroxydimethyl ketone; Chromelin; CTF A 00816; Dihyxal; Otan; Oxantin; Oxatone; Soleal; Triulose; Viticolor Structural Class: Ketone, ketotriose compound Structure. Molecular Formula. and Molecular Weight: 0 II /c"-.
    [Show full text]
  • Physics of Information in Nonequilibrium Systems A
    PHYSICS OF INFORMATION IN NONEQUILIBRIUM SYSTEMS A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI`I AT MANOA¯ IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN PHYSICS MAY 2019 By Elan Stopnitzky Thesis Committee: Susanne Still, Chairperson Jason Kumar Yuriy Mileyko Xerxes Tata Jeffrey Yepez Copyright c 2019 by Elan Stopnitzky ii To my late grandmother, Rosa Stopnitzky iii ACKNOWLEDGMENTS I thank my wonderful family members Benny, Patrick, Shanee, Windy, and Yaniv for the limitless love and inspiration they have given to me over the years. I thank as well my advisor Susanna Still, who has always put great faith in me and encouraged me to pursue my own research ideas, and who has contributed to this work and influenced me greatly as a scientist; my friend and collaborator Lee Altenberg, whom I have learned countless things from and who contributed significantly to this thesis; and my collaborator Thomas E. Ouldridge, who also made important contributions. Finally, I would like to thank my partner Danelle Gallo, whose kindness and support have been invaluable to me throughout this process. iv ABSTRACT Recent advances in non-equilibrium thermodynamics have begun to reveal the funda- mental physical costs, benefits, and limits to the use of information. As the processing of information is a central feature of biology and human civilization, this opens the door to a physical understanding of a wide range of complex phenomena. I discuss two areas where connections between non-equilibrium physics and information theory lead to new results: inferring the distribution of biologically important molecules on the abiotic early Earth, and the conversion of correlated bits into work.
    [Show full text]
  • Magnetite Plaquettes Are Naturally Asymmetric Materials in Meteorites
    1 (Revision 2) 2 Magnetite plaquettes are naturally asymmetric materials in meteorites 3 Queenie H. S. Chan1, Michael E. Zolensky1, James E. Martinez2, Akira Tsuchiyama3, and Akira 4 Miyake3 5 1ARES, NASA Johnson Space Center, Houston, Texas 77058, USA. 6 2Jacobs Engineering, Houston, Texas 77058, USA. 7 3Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 8 606-8502, Japan. 9 10 Correspondence to: Queenie H. S. Chan. Correspondence and requests for materials should be 11 addressed to Q.H.S.C. (Email: [email protected]) 12 13 Abstract 14 Life on Earth shows preference towards the set of organics with particular spatial configurations. 15 Enantiomeric excesses have been observed for α-methyl amino acids in meteorites, which 16 suggests that chiral asymmetry might have an abiotic origin. A possible abiotic mechanism that 17 could produce chiral asymmetry in meteoritic amino acids is their formation under the influence 18 of asymmetric catalysts, as mineral crystallization can produce spatially asymmetric structures. 19 Although magnetite plaquettes have been proposed to be a possible candidate for an asymmetric 20 catalyst, based on the suggestion that they have a spiral structure, a comprehensive description of 21 their morphology and interpretation of the mechanism associated with symmetry-breaking in 22 biomolecules remain elusive. Here we report observations of magnetite plaquettes in 1 23 carbonaceous chondrites (CCs) which were made with scanning electron microscopy and 24 synchrotron X-ray computed microtomography (SXRCT). We obtained the crystal orientation of 25 the plaquettes using electron backscatter diffraction (EBSD) analysis. SXRCT permits 26 visualization of the internal features of the plaquettes.
    [Show full text]
  • Arxiv:1910.06396V4 [Physics.Pop-Ph] 12 Jun 2021 ∗ Rmtv Ieeitdi H R-Oa Eua(Vni H C System)
    Nebula-Relay Hypothesis: Primitive Life in Nebula and Origin of Life on Earth Lei Feng1,2, ∗ 1Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023 2Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing University – Purple Mountain Observatory, Nanjing 210093, China Abstract A modified version of panspermia theory, named Nebula-Relay hypothesis or local panspermia, is introduced to explain the origin of life on Earth. Primitive life, acting as the seeds of life on Earth, originated at pre-solar epoch through physicochemical processes and then filled in the pre- solar nebula after the death of pre-solar star. Then the history of life on the Earth can be divided into three epochs: the formation of primitive life in the pre-solar epoch; pre-solar nebula epoch; the formation of solar system and the Earth age of life. The main prediction of our model is that primitive life existed in the pre-solar nebula (even in the current nebulas) and the celestial body formed therein (i.e. solar system). arXiv:1910.06396v4 [physics.pop-ph] 12 Jun 2021 ∗Electronic address: [email protected] 1 I. INTRODUCTION Generally speaking, there are several types of models to interpret the origin of life on Earth. The two most persuasive and popular models are the abiogenesis [1, 2] and pansper- mia theory [3]. The modern version of abiogenesis is also known as chemical origin theory introduced by Oparin in the 1920s [1], and Haldane proposed a similar theory independently [2] at almost the same time. In this theory, the organic compounds are naturally produced from inorganic matters through physicochemical processes and then reassembled into much more complex living creatures.
    [Show full text]
  • Molecular Asymmetry in Prebiotic Chemistry: an Account from Meteorites
    life Review Molecular Asymmetry in Prebiotic Chemistry: An Account from Meteorites Sandra Pizzarello School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA; [email protected]; Tel.: +1-480-965-3370 Academic Editors: Pier Luigi Luisi and David Deamer Received: 8 February 2016; Accepted: 7 April 2016; Published: 13 April 2016 Abstract: Carbonaceous Chondrite (CC) meteorites are fragments of asteroids, solar planetesimals that never became large enough to separate matter by their density, like terrestrial planets. CC contains various amounts of organic carbon and carry a record of chemical evolution as it came to be in the Solar System, at the time the Earth was formed and before the origins of life. We review this record as it pertains to the chiral asymmetry determined for several organic compounds in CC, which reaches a broad molecular distribution and enantiomeric excesses of up to 50%–60%. Because homochirality is an indispensable attribute of extant polymers and these meteoritic enantiomeric excesses are still, to date, the only case of chiral asymmetry in organic molecules measured outside the biosphere, the possibility of an exogenous delivery of primed prebiotic compounds to early Earth from meteorites is often proposed. Whether this exogenous delivery held a chiral advantage in molecular evolution remains an open question, as many others regarding the origins of life are. Keywords: meteorites; asteroids; abiotic; prebiotic; chemical evolution; enantiomeric excess 1. Carbon-Containing Meteorites and Cosmochemical Evolution One of the paradigms of chemical evolution proposes that the abiotic formation of increasingly complex molecules throughout cosmochemical and Earthly processes could eventually lead to life’s precursor molecules.
    [Show full text]
  • Experimental Evidence for Glycolaldehyde and Ethylene Glycol Formation by Surface Hydrogenation of CO Molecules Under Dense Molecular Cloud Conditions
    Experimental evidence for Glycolaldehyde and Ethylene Glycol formation by surface hydrogenation of CO molecules under dense molecular cloud conditions G. Fedoseev1, a), H. M. Cuppen2, S. Ioppolo2, T. Lamberts1, 2 and H. Linnartz1 1Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, PO Box 9513, NL 2300 RA Leiden, The Netherlands 2Institute for Molecules and Materials, Radboud University Nijmegen, PO Box 9010, NL 6500 GL Nijmegen, The Netherlands Abstract This study focuses on the formation of two molecules of astrobiological importance - glycolaldehyde (HC(O)CH2OH) and ethylene glycol (H2C(OH)CH2OH) - by surface hydrogenation of CO molecules. Our experiments aim at simulating the CO freeze-out stage in interstellar dark cloud regions, well before thermal and energetic processing become dominant. It is shown that along with the formation of H2CO and CH3OH – two well established products of CO hydrogenation – also molecules with more than one carbon atom form. The key step in this process is believed to be the recombination of two HCO radicals followed by the formation of a C-C bond. The experimentally established reaction pathways are implemented into a continuous-time random-walk Monte Carlo model, previously used to model the formation of CH3OH on astrochemical time-scales, to study their impact on the solid-state abundances in dense interstellar clouds of glycolaldehyde and ethylene glycol. Key words: astrochemistry – methods: laboratory – ISM: atoms – ISM: molecules – infrared: ISM. 1 Introduction Among approximately 180 molecules identified in the inter- and circumstellar medium over 50 molecules comprise of six or more atoms. For astrochemical standards, these are seen as ‘complex’ species.
    [Show full text]
  • Life in the Solar System
    Adv. Space Res. Vol. 24, No. 4, pp. 417-433, 1999 Pergamon 0 1999 COSPAR. Published by Elsevier Science Ltd. AH rights reserved Printed in Great Britain 0273-1177/99 $20.00 + 0.00 www.elaevier.nl/locate/asr PII: SO273I 177(99)00457-3 LIFE IN THE SOLAR SYSTEM A. Brack Centre de Biophysique Moleculaire, CNRS, Rue Charles Sadron, Orleans, France. Fax: +33-2-38-63-15-17; brack@cnrs-orleansfr ABSTRACT Life, defined as a chemical system capable of transferring its molecular information via self-replication and also capable of evolving, must develop within a liquid to take advantage of the diffusion of complex molecules. On Earth, life probably originated from the evolution of reduced organic molecules in liquid water. Organic matter might have been formed in the primitive Earth’s atmosphere or near hydrothermal vents. A large fraction of prebiotic organic molecules might have been brought by extraterrestrial- meteoritic and cometary dust grains decelerated by the atmosphere. Any celestial body harboring permanent liquid water may therefore accumulate the ingredients that generated life on the primitive Earth. The possibility that life might have evolved on early Mars when water existed on the surface marks it as a prime candidate in a search for bacterial life beyond the Earth. Europa has an icy carapace. However, cryovolcanic flows at the surface point to a possible water subsurface region which might harbor a basic life form. The atmosphere and surface components of Titan are also of interest to exobiology for insight into a hydrocarbon-rich chemically evolving world. One-handed complex molecules and preferential isotopic fractionation of carbon, common to all terrestrial life forms, can be used as basic indicators when searching for life beyond the Earth.
    [Show full text]
  • Pyrolysis of the Simplest Carbohydrate, Glycolaldehyde (CHO-CH2OH), and Glyoxal in a Heated Microreactor
    Lawrence Berkeley National Laboratory Recent Work Title Pyrolysis of the Simplest Carbohydrate, Glycolaldehyde (CHO-CH2OH), and Glyoxal in a Heated Microreactor. Permalink https://escholarship.org/uc/item/9tw3g0r4 Journal The journal of physical chemistry. A, 120(14) ISSN 1089-5639 Authors Porterfield, Jessica P Baraban, Joshua H Troy, Tyler P et al. Publication Date 2016-04-01 DOI 10.1021/acs.jpca.6b00652 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Pyrolysis of the Simplest Carbohydrate, Glycolaldehyde (CHO-CH2OH), and Glyoxal in a Heated Micro-Reactor Jessica Porterfield1, Joshua H. Baraban1, Tyler P. Troy2, Musahid Ahmed2, Michael C. McCarthy3, Kathleen M. Morgan4, John W. Daily5, Thanh Lam Nguyen6, John F. Stanton6, G. Barney Ellison1 1Department of Chemistry and Biochemistry, University of Colorado, Boulder, 80309- 0215, U.S.A., 2Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, CA 94720, U.S.A., 3Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, 4Department of Chemistry , Xavier University of Louisiana , New Orleans, LA 70125-1098, 5Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309-0427, U.S.A., and 6Department of Chemistry; University of Texas at Austin; Austin, TX 78712. E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] Email: [email protected] J. Physical Chemistry A (revised, March 2016) - 2 - Abstract Both glycolaldehyde and glyoxal have been pyrolyzed in a set of flash- pyrolysis micro-reactors.
    [Show full text]
  • Quantifying Hydrogen-Deuterium Exchange of Meteoritic Dicarboxylic Acids During Aqueous Extraction
    Quantifying hydrogen-deuterium exchange of meteoritic dicarboxylic acids during aqueous extraction Item Type Article; text Authors Fuller, M.; Huang, Y. Citation Fuller, M., & Huang, Y. (2003). Quantifying hydrogendeuterium exchange of meteoritic dicarboxylic acids during aqueous extraction. Meteoritics & Planetary Science, 38(3), 357-363. DOI 10.1111/j.1945-5100.2003.tb00271.x Publisher The Meteoritical Society Journal Meteoritics & Planetary Science Rights Copyright © The Meteoritical Society Download date 29/09/2021 19:01:11 Item License http://rightsstatements.org/vocab/InC/1.0/ Version Final published version Link to Item http://hdl.handle.net/10150/655665 Meteoritics & Planetary Science 38, Nr 3, 357–363 (2003) Abstract available online at http://meteoritics.org Quantifying hydrogen-deuterium exchange of meteoritic dicarboxylic acids during aqueous extraction Megan FULLER and Yongsong HUANG* Department of Geological Sciences, Brown University, Providence, Rhode Island 02912–1846, USA *Corresponding author. E-mail: [email protected] (Received 15 July 2002; revision accepted 8 January 2003) Abstract–Hydrogen isotope ratios of organic compounds in carbonaceous chondrites provide critical information about their origins and evolutionary history. However, because many of these compounds are obtained by aqueous extraction, the degree of hydrogen-deuterium (H/D) exchange that occurs during the process needs to be quantitatively evaluated. This study uses compound- specific hydrogen isotopic analysis to quantify the H/D exchange during aqueous extraction. Three common meteoritic dicarboxylic acids (succinic, glutaric, and 2-methyl glutaric acids) were refluxed under conditions simulating the extraction process. Changes in δD values of the dicarboxylic acids were measured following the reflux experiments. A pseudo-first order rate law was used to model the H/D exchange rates which were then used to calculate the isotope exchange resulting from aqueous extraction.
    [Show full text]