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TOPIC: Ingredients for life


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Complex organic compounds
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 Organics Probably Formed Easily in Early Solar System
 
Complex organic compounds, including many important to life on Earth, were readily produced under conditions that likely prevailed in the primordial solar system. Scientists at the University of Chicago and NASA Ames Research Centre came to this conclusion after linking computer simulations to laboratory experiments.
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RE: Ingredients for life
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NASA Detects Metabolic Precursors in Meteorite Dust

NASA scientists have found organic compounds associated with cellular respiration in carbonaceous meteorites, and simulated space-like conditions in the laboratory to determine how the compounds could have formed in deep space billions of years ago.
The compounds belong to newly discovered classes of compounds in meteorites, specifically keto acids, hydroxy tricarboxylic acids and tricarboxylic acids, some of which are members of the citric acid cycle. This cycle is part of a process in which living cells break down organic fuel molecules in the presence of oxygen to harvest the energy they need to grow and divide. This metabolic process occurs in most plants, animals, fungi, and many bacteria. The discovery adds to a growing body of evidence that a variety of organic compounds delivered to Earth by carbonaceous meteorites may have played a role in the origin and/or evolution of biochemical pathways. Previously, most members of the citric acid cycle had not been identified in extraterrestrial sources.

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Meteorites: Tool kits for creating life on Earth

Meteorites hold a record of the chemicals that existed in the early Solar System and that may have been a crucial source of the organic compounds that gave rise to life on Earth. Since the 1960s, scientists have been trying to find proof that nucleobases, the building blocks of our genetic material, came to Earth on meteorites. New research, published next week in the Proceedings of the National Academy of Sciences, indicates that certain nucleobases do reach the Earth from extraterrestrial sources, by way of certain meteorites, and in greater diversity and quantity than previously thought.
Extensive research has shown that amino acids, which string together to form proteins, exist in space and have arrived on our planet piggybacked on a type of organic-rich meteorite called carbonaceous chondrites. But it has been difficult to similarly prove that the nucleobases found on meteorite samples are not due to contamination from sources on Earth.

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CERN lends a hand to the origin of life

In the beginning, the universe came into existence as a hot sea of barely-there particles. Soon, matter as we know it appeared: protons, neutrons and electrons, atoms formed. Next in the line were the first organic molecules and then, finally, life.
It's a weird twist of fate that large-scale science investigations into these areas have appeared in the same order. While physicists at CERN currently study the origin of the universe and the origin of matter, in the future they may be asked to help crack the origin of life too. On May 20, a small group of chemists and biologists gathered at CERN for a brainstorming workshop discussing ideas about the origin of life, and to hear from CERN experts about how to organize a scientific community from disparate research groups and how to access powerful computational resources.

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Asteroids make life's raw materials

Were asteroids the factories that created life's building blocks? For the first time, rocks from an asteroid have been shown to power the synthesis of life's essential chemicals.
The asteroid in question fell to Earth on 28 September 1969, landing on the outskirts of the village of Murchison in Victoria, Australia. Tests showed it was laced with amino acids and some of the chemicals found in our genetic material.
The discovery suggested that space was not the chemically sterile place it was once thought to be, and that organic chemistry was widespread. It hinted that the molecules life needed to get started could have been produced in space, before dropping to Earth.

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Formaldehyde: Poison could have set the stage for the origins of life

Formaldehyde, a poison and a common molecule throughout the universe, is likely the source of the solar system's organic carbon solids - abundant in both comets and asteroids. Scientists have long speculated about the how organic, or carbon-containing, material became a part of the solar system's fabric. New research from Carnegie's George Cody, along with Conel Alexander and Larry Nittler, shows that these complex organic solids were likely made from formaldehyde in the primitive solar system. Their work is published online April 4 by the Proceedings of the National Academy of Sciences.
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Did clay mould life's origins?

Professor Don Fraser from the Department of Earth Sciences has carried out neutron scattering experiments to try to find out more about the role of geochemistry in determining the origin of our amino acids - key building blocks of life on Earth - and specifically why the DNA-coded amino acids that make up our proteins are all left-handed.
Clay was suggested by the crystallographer John Bernal as a means of concentrating primitive biomolecules onto its surface so as to be available for further reactions. Clays again became the focus of studies more recently when James Ferris showed that they can act as catalysts for the formation of long strands of RNA, which with proteins and DNA are major compounds essential for the origin of life.

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Volcanoes Helped Spread Life on Earth

An old experiment, rediscovered after more than 50 years, may demonstrate how volcanoes and possibly chemical reactions far from primitive Earth in outer space played a role in creating the first amino acids, the building blocks of life.
In 1953, chemists Harold Urey and Stanley Miller performed a landmark experiment intended to mimic the primordial conditions that created the first amino acids, by exposing a mix of gases to a lightning-like electrical discharge. Five years later, in 1958, Miller performed another variation on this experiment. This time he added hydrogen sulfide, a gas spewed out by volcanoes, to the mix.

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Abundant ammonia aids life's origins

An important discovery has been made with respect to the possible inventory of molecules available to the early Earth. Scientists led by Sandra Pizzarello, a research professor at Arizona State University, found large amounts of ammonia in a primitive Antarctic asteroid. This high concentration of ammonia could account for a sustained source of reduced nitrogen essential to the chemistry of life.
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Meteorite cargo could solve origin-of-life riddle

A chemical vital for life on Earth may have arrived ready-made from space. Unexpectedly, a chondritic meteorite has been found to contain large amounts of ammonia, a nitrogen-rich chemical needed to form the basic building blocks of life, including proteins, DNA and RNA.
Explaining how the early Earth gained enough ammonia for life to begin has been a puzzle, because sunlight rapidly destroys ammonia gas in the atmosphere. Furthermore, geological samples suggest that the environment was chemically neutral, rather than the reducing conditions that would have favoured ammonia formation.

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