Theoretical origin of life: interview with Stanley Miller (Introduction)

by David Turell , Wednesday, September 16, 2015, 00:57 (3356 days ago) @ David Turell

Miller of the famous Miller-Urey lightning in a bottle experiment. They got 13 of the 20 essential amino acids in the tarry gunk they created. They used a reducing atmosphere which is now not thought to be correct in the proportions of gases, but he insists the atmosphere must be reducing:-http://www.astrobio.net/news-exclusive/primordial-recipe-spark-and-stir/-"AB: What is your current opinion on the need for a primitive reducing atmosphere for pre-biotic life to take hold 3.5 to 3.8 billion years ago?- "SM: I have not found an alternative to disprove the need for a primitive reducing atmosphere.- "AB: Do you believe that material transported on meteors or comets is insufficient to seed life, if such amino acids were successfully transported intact to the surface of the Earth? -"SM: Meteorite and other exogenous contributions become very important only if the earth had a neutral atmosphere. However, if the only sources of organic compounds under such conditions were the very small number of compounds produced with a CO2 rich atmosphere and delivered from outside, the amount may be too low for the origin of life.-" AB: Since many astrobiologists are currently examining hydrothermal vents, in search of extremophiles, does the prebiotic chemistry actually get decomposed rather than enhanced by the presence of such ocean venting?- "SM: Locating extremophiles is not relevant to the synthesis of organic compounds necessary for life, as the conditions of such ocean venting decomposes rather than enhances prebiotic chemistry. -***-"There are other hurdles in the progression from simple molecules to complex life that are large research topics. Producing amino acids and nucleotides , and getting them to polymerize into proteins and nucleic acids (typically, RNA), are parts of a vast and ongoing ‘origins' discussion. But RNA is a relatively fragile component (compared to DNA, or other biomolecules), and thus again its first appearance remains subject to the particular local conditions of the early Earth. To stabilize or catalyze the first biomolecules, clay crystals and vesicle reactions may have helped. No one has been able to synthesize RNA without the help of protein catalysts or nucleic acid templates."-Comment: Startng life is not easy. Note "RNA is fragile".