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chapter 26 & 8

chapter 26 & 8 - 1 Explain Oparin and Haldanes...

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1. Explain Oparin and Haldane’s theory of chemical evolution, and Miller and Urey’s experiment that validated it. Oparin and Haldane hypothesized that the conditions on primal earth were composed of chemical reactions that synthesized organic compounds from inorganic foundations. However, this could not occur in present life because there is now a vital presence of oxygen produced by photosynthetic life. Our present oxygen-filled atmosphere is not conducive to spontaneous synthesis of molecules because the oxygen attacks chemical bonds, which in turn extracts electrons. Pre- oxygen Earth, derived mainly from volcanic vapors, enhanced the formation of complex molecules due to the strong presence of electrons. Miller and Urey then took this postulation and turned it into a laboratory experiment by creating the comparable environment. The atmosphere in the model consisted of H20, H2, CH4, NH3 and a warm flask of water simulated the primeval sea. Sparks were used to imitate the effect of lightening while a condenser cooled the atmosphere. The solution changed from clear to murky as material circulated through the apparatus. After the duration of one week, Miller and Urey had found a variety of organic compounds, including some of the amino acids that make up proteins of organisms. 2. Describe the major steps that most likely occurred in the formation of living organisms? Raindrops or waves may have splashed dilute solutions of organic monomers onto fresh lava and then rinsed polypeptides and other polymers back into the sea. Alternatively, deep sea vents, where gases and super heated water with dissolved minerals escape from earths interior, may have been locales for the abiotic synthesis of both organic monomers and polymers. RNA is hypothesized to have been the first genetic material. Short polymers of ribonucleotides have been produced abiotically in laboratory experiments. Protobionts could have formed spontaneously from abiotically produced organic compounds.
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