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A Review Article on the Chemical Origin of Life Available online at http://www.journalijdr.com ISSN: 2230-9926 International Journal of Development Research Vol. 07, Issue, 08, pp.14851-14856, August, 2017 ORIGINAL RESEARCH ARTICLE ORIGINAL RESEARCH ARTICLE OPEN ACCESS A REVIEW ARTICLE ON THE CHEMICAL ORIGIN OF LIFE Shaik. Munwar, Harikrishna, P., Sadulla, S.K., Nagarjuna, P. and Vamsikrishna,V. Department of pharmaceutical chemistry, Narasaraopeta institute of pharmaceutical sciences, Kotappakonda road, Yallamanda post, Narasaraopeta, Guntur district, Andhra Pradesh -522601 ARTICLE INFO ABSTRACT Article History: This is an explanation of how life might have originated. It is written for non-specialists. The Received 28th May, 2017 cooling by seawater of rocks under the floor of the ocean, played an important role in the origin Received in revised form of life. Such a process might seem remote from our everyday knowledge of life but it has now 19th June, 2017 been known for more than twenty years that genetically primitive micro-organisms are to be Accepted 20th July, 2017 found living at warm springs on the ocean floor. th Published online 30 August, 2017 Key words: Abiogenesis, RNA, DNA, Replication and Phylogenic. *Corresponding author Copyright ©2017, Shaik. Munwar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Citation: Shaik. Munwar, Harikrishna, P., Sadulla, S.K., Nagarjuna, P. and Vamsikrishna, V., 2017. “A Review Article on the Chemical Origin of INTRODUCLife”, InternationalTION Journal of Development Research, 7, (08), 14851-14856. INTRODUCTION Chlorophyll is based upon a porphyrin ring derived from Abiogenesis or informally the origin of life is the natural amine monomer units, and is important in the capture of the process by which life arises from non-living matter, such as energy needed for life. Nucleic acid monomers are made from simple organic compounds. Abiogenesis is studied through a a carbohydrate monosaccharide, a nitrogenous base and one or combination of paleontology, laboratory experiments and more high energy phosphate groups. When joined together extrapolation from the characteristics of modern organisms, they form the unit of inheritance, the gene, made and aims to determine how pre-life chemical reactions gave from DNA or RNA, which translates the genetic information rise to life on Earth. The study of abiogenesis can into protein structures. The monomer unit of a protein is be geophysical, chemical, or biological, with more recent usually one of 20 amino acids, comprising an amine group, a approaches attempting a synthesis of all three. Life itself is hydrocarbon, and a carboxylic acid. Through a condensation dependent upon the specialized chemistry of carbon and water reaction, in which the carboxylic acid of one amino acid is and is largely based upon five different families of linked to the amine of another with removal of a water chemicals. Lipids are fatty molecules comprising large molecule, a peptide bond is formed. Polymers of amino acids chemical chains of hydrocarbons and play an important role in are termed proteins and these molecules provide the structure of living cell membranes, actively and passively many catalytic metabolic functions for living processes. Any determining the transport of other molecules into and out of successful theory of abiogenesis must explain the origins and cells. Carbohydrates are sugars, and as monomer units can be interactions of these five classes of molecules. Many assembled into polymers called polysaccharides, such approaches to abiogenesis investigate how self- as cellulose, the rigid chemical of most plant cell replicating molecules, or their components, came into walls. Nitrogenous bases are organic molecules in which existence. It is generally thought that current life on Earth is the amine group of nitrogen, combined with two hydrogen descended from an RNA world, although RNA-based life may atoms, plays an important part. not have been the first life to have existed. 14852 Shaik. Munwar et al. A Review Article on the Chemical Origin of Life The classic Miller–Urey experiment and similar research How did life begin on Earth? demonstrated that most amino acids, the basic chemical constituents of the proteins used in all living organisms, can be Scientists do not know how life began on Earth. They do know synthesized from inorganic compounds under conditions that the early Earth's atmosphere was very different from the intended to replicate those of the early Earth. Various external atmosphere now. In 1952, Stanley Miller was working with sources of energy that may have triggered these reactions have Harold C. Urey designed an experiment to see how complex been proposed, including lightning and radiation. Other organic molecules might have formed under the conditions of approaches ("metabolism-first" hypotheses) focus on early Earth. What is the origin of the earth? understanding how catalysis in chemical systems on the early Earth might have provided the precursor molecules necessary Origin of Earth. for self-replication. Complex organic molecules have been found in the Solar System and in interstellar space, and these Earth, along with the other planets, is believed to have been molecules may have provided starting material for the born 4.5 billion years ago as a solidified cloud of dust and development of life on Earth. Oceans may have appeared gases left over from the creation of the Sun. first in the Hadean Eon, as soon as two hundred million years (200 Ma) after the Earth was formed, in a hot 100 °C (212 °F) Where did the life come from? reducing environment, and the pH of about 5.8 rose rapidly towards neutral. This has been supported by the dating of Simple organic molecules, similar to the nucleotide shown 4.404 Ga-old zircon crystals from below, are the building blocks of life and must have been metamorphosed quartzite of Mount Narryer in the Western involved in its origin. Experiments suggest that organic Australia Jack Hills of the Pilbara, which are evidence that molecules could have been synthesized in the atmosphere of oceans and continental crust existed within 150 Ma of Earth's early Earth and rained down into the oceans. formation. Despite the likely increased volcanism and existence of many smaller tectonic "platelets," it has been Who proposed the chemical evolution of life? suggested that between 4.4 and 4.3 Ga (billion year), the Earth was a water world, with little if any continental crust, an In the first stage of chemical evolution, molecules in the extremely turbulent atmosphere and a hydrosphere subject to primitive environment formed simple organic substances, such intense ultraviolet (UV) light, from a T Tauri stage as amino acids. This concept was first proposed in 1936 in a Sun, cosmic radiation and continued bolide impacts book entitled, "The Origin of Life on Earth," written by the Russian scientist, Aleksandr Ivanovich Oparin. Chemical Origin of Life When did life begin? The chemical origin of life refers to the conditions that might have existed and therefore promoted the first When Did Life on Earth Begin? Ask a Rock. Does the first replicating life forms. It considers the physical evidence of life date to3.85 billion years ago (Ga), or 3.65 Ga? and chemical reactions that could have led to early replicator A 200-million-years discrepancy may seem trivial almost 4 molecules. billion years after the fact. How did life come to be? The first living things on Earth, single-celled micro-organisms or microbes lacking a cell nucleus or cell membrane known as prokaryotes, seem to have first appeared on Earth almost four billion years ago, just a few hundred million years after the formation of the Earth itself. How did the human start? Human evolution is the lengthy process of change by which people originated from apelike ancestors. ... Humans first evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between What are the origins of life? 6 and 2 million years ago come entirely from Africa. How did humans evolve? The origin of life is a scientific problem which is not yet solved. There are plenty of ideas, but few clear facts. It is Humans did not evolve from apes, gorillas or chimps. We are generally agreed that all life today evolved by common all modern species that have followed different evolutionary descent from a single primitive life form. paths, though humans share a common ancestor with some primates, such as the African ape. The timeline of human What is the chemical evolution of life? evolution is long and controversial, with significant gaps. The formation of complex organic molecules from simpler What is the RNA world hypothesis and why is it called inorganic molecules through chemical reactions in the oceans that? during the early history of the Earth; the first step in the development of life on this planet. The period of chemical According to the RNA World Hypothesis, life later evolved to evolution lasted less than a billion years. use DNA and proteins due to RNA's relative instability and 14853 International Journal of Development Research, Vol. 07, Issue, 08, pp. 14851-14856, August, 2017 poorer catalytic properties, and gradually, ribozymes became unlikely to have happened. Other nucleic acids other than increasingly phased out. The ribosome, a large molecular RNA have been suggested as well, such as the more esoteric machine that drives protein synthesis, is a ribozyme. PNA or TNA. A study in 2015 suggests the missing link in this RNA puzzle may have been found. Can RNA replicate? Chilly Start RNA should in theory be able to self replicate without the help of proteins however this is not seen in nature. There Ice might have covered the oceans 3 billion years ago, as the are RNA molecules catalyse chemical reactions, a role usually sun was about a third less luminous than it is now, scientists carried out only by protein enzymes, these are called say.
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