Chapter 26 - Chapter 26-The Tree of Life Concept 26.1...

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27/02/2008 19:51:00 Concept 26.1 Four main stages that produced simple cells on Earth: o 1) The  abiotic  (nonliving) synthesis of small organic molecules Such as amino acids and nucleotides o 2) The joining of these small molecules into polymers. Including proteins and nucleic acids o 3) The packaging of these molecules into “protobionts,” droplets with  membranes that maintained an internal chemistry different from that of  their surroundings o 4)The origin of self-replicating molecules that eventually made  inheritance possible.   The Earth and other planets of the solar system formed about 4.6 billion years  ago, condensing from a vast cloud of dust and rocks that surrounded the  young sun.   In the 1920’s, Oparin and Haldane independently postulated that Earth’s early  atmosphere had been an environment where organic compounds could have  formed from simple molecules. o The energy for this organic synthesis was lighting or intense UV  radiation. Miller and Urey tested Oparin and Haldane’s hypothesis by creating  laboratory conditions comparative to those of early Earth. o Their apparatus yielded a variety of amino acids found in organisms  today, along with other organic compounds.   Protobionts-  area aggregates of abiotically produced molecules surrounded  by a membrane or membrane-like structure. o Protobionts exhibit some of the properties associated with life,  including simple reproduction and membrane-like structure.   Also had an internal chemical environment different from that of  their surroundings. The first genetic material was probably 
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This note was uploaded on 04/07/2008 for the course BIL 160 taught by Professor Krempels during the Spring '08 term at University of Miami.

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Chapter 26 - Chapter 26-The Tree of Life Concept 26.1...

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