Astro midterm 2 Review

Astro midterm 2 Review - AstroReview...

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Astro Review 19:03 We haven’t found sweet, close civilizations yet  Universal properties of life as we know it Life is catalytic o there should be significant deviations from what chemical kinetics predicts o life modifies its environment o life consumes energy o life creates waste products o life is exothermic o life use thermodynamic disequilibria to build and maintain other  thermodynamic disequilibria (in open systems or within a “wall”) Life is genetic o there will be some system for storing and propagating information o there will be molecular distributions with significant capacity for complexity Life replicates and evolves o there will be evidence of replication of structures and complexity o there may be evidence (structural and chemical) of evolution of form and  function common ancestry makes sense because on earth all organisms share the same  nucleotides  Ingredients for life
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Lipids for cell wall Nucleic acid Proteins Conditions for (earth) life Essential elements o Carbon, nitrogen, phosphorous, sulpher, iron Continuous source of energy Liquid water (and the temps that allow it) 5 steps to the origin of life conditions result in the creation of certain basic small molecules (monomers)  of life o amino acids phospholipids (of an appropriate length) can spontaneously form lipid bilayers o UV radiation + Amphiphilic molecules (polar end+nonpolar end) in  interstellar ice = spontaneous vesicle formation polymerization of nucleotides into random RNA molecules ribozymes that catalyze peptidyl transfer proteins outcompete ribozymes in catalytic ability organic materials were delivered to earth endogenicly (from earth)
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o hydrothermal vents o miller-uray synthesis o impact o iron-sulpher world (polymerization) Exogenicly (from outside) o Supernova o Comets o Panspermia Life was delivered to earth Theory states that there can be no origin of life from non-living  organisms in the finite past Without intervention life must have always existed Nebular chem. Organics form in-nebuli at temps = a few 100K Other molecules are formed by a process o Cold temps freeze shit into microscopic grains o Cosmic radiation breaks bonds and ice forms new ones PAH’s Smell like hotdogs Benzene rings
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10-15% of galactic carbon might be important to early life Miller experiment Ingredients o Hydrogen gas o Nitrogen gass o Carbon dioxide o Water o Ammonia o Methane Ingredients + electricity = amino acids +concentration-o-amino acids = +interactions = +complex molecules nucleic acids either not formed or highly unstable o
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This note was uploaded on 12/10/2010 for the course BIOL 205 taught by Professor Kramer during the Winter '08 term at McGill.

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Astro midterm 2 Review - AstroReview...

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