Biology Exam #2 Notes

Biology Exam #2 Notes - Biology Exam #2 Notes Lecture #1:...

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Biology Exam #2 Notes Lecture #1: Keywords: Earth formed 4.6 billion years ago, reducing atmosphere, abiotic synthesis, Oparin-Haldane, Miller-Urey,  prebiotic soup, ribozyme, RNA world, autotroph/heterotrophy, endosymbiosis, homology, homoplasy, taxon,  taxonomy, systematic, phylogeny, cladistics, clade, parsimony, synapomorphy, plesiomorphy, monophyletic,  paraphyletic, Linnaeus, Kingdom to Species, binomial, three domains. Virus genome, cpsid, bacteriophage.  Archaea [halophile, thermophile, methanogens], peptidoglycan: Gram positive, lipopolysaccharide is Gram  negative, cynobacteria, heterocysts, nitrogen fixation, chlorophyll A, plastid. Lecture: Origin of life Kingdoms Viruses and prokaryotes Conditions on early life     o Earth is ~4.6 billion years    FOSSILS o Atmosphere had little free oxygen Included carbon dioxide, water, carbon monoxide, hydrogen, nitrogen Maybe also NH 3 , H 2 S, CH 4 o REDUCING atmosphere Nothing rusts, not a lot of oxygen Life could never evolve Requirements for chemical evolution to produce life o Absence of oxygen -> why? Oxidation destroys organics -> therefore, reducing atmosphere o Energy -> what kind? What for?? Covalent bonds o Chemical “building blocks” -> what kind? Where from?
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Amino acids, etc. o Sufficient time Prebiotic soup hypothesis     o Ocean   lightning was energy form for spontaneous life Molecules formed near surface o Abiotic synthesis using steam, sparks, water, ammonia, hydrogen, and methane : experimentally demonstrated that amino acids can be made  abiotically o Abiotically – made without life; made spontaneously; ie. With lightning abiotic synthesis of monomers 13 amino acids, glycine was the most None formed in oxygen was added By adding HCN   make nucleotide base adenine and other bases abiotically o Ocean fills with all of these things (ie. The soup) o Sugars, nucleotides, amino acids form spontaneously Iron-Sulfur World hypothesis     o Organic molecules formed at hydrothermal vents on the ocean floor o Lab simulations show catalyst effects of iron and nickel sulfides Requirements for evolution: hereditary material     o RNA world – why not DNA? Self-replicating RNA molecules Function as both enzymes and substrate for replication Ribozyme is enzymatic RNA
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First step in evolution of the DNA/RNA/protein system o In RNA world, ribozymes catalyzed protein cells The First Cells     o Heterotrophs that feed on organic molecules Do not need to make own food because there is so much in ocean (soup) o
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Biology Exam #2 Notes - Biology Exam #2 Notes Lecture #1:...

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