essay1 - Describe the steps by which inorganic substances...

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Describe the steps by which inorganic substances may have undergone chemical evolution to yield the complex system of organic chemicals we recognize as a living thing. Which of these steps can be duplicated in the laboratory? Life did not appear on Earth until about 3.5 billion years ago, which is about 2 billion years after the formation of the earth, which was created by either a condensation of intergalactic dust or from a piece of the sun that broke off. The early atmosphere of Earth contained no free oxygen because all the oxygen was tied up in water or oxides. This is important because the reducing, or electron adding, nature of the atmosphere was important for the survival of the anaerobes, which were predominate, would have been devastated. Thus, the production of organic molecules was a slow and long process but it said to have occurred in four stages: 1) abiotic synthesis of organic monomers, 2) abiotic synthesis of polymers, 3) formation of protobionts and 4) origin of genetic information. 1. In the 1920’s Oparin and Haldane postulated that the reducing nature of the atmosphere, due to the lack of free molecular oxygen, and high UV radiation enhanced reactions joining simple molecules to produce the first organic molecules. a. The atmosphere was composed mainly of methane, ammonia, water vapor, and carbon dioxide. Originally, the carbon atoms were present as metallic carbides. These could have reacted with water to for m acetylene and then
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This note was uploaded on 08/04/2008 for the course BIOL 101 taught by Professor Hogan during the Fall '08 term at UNC.

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essay1 - Describe the steps by which inorganic substances...

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