01:119:115 Lecture Notes - Lecture 4: Organelle, Proterozoic, Electronegativity
12 Dec 2016
School
Department
Course
Professor
Document Summary
Lecture 4 - origin of life: chemical evolution: from non-living to living. 4 requirements for abiotic synthesis to have occurred: conditions of early earth: little or no free oxygen. Oxygen breaks down (oxidizes so o2) not conducive to building. Oxidation is losing electrons, reduction is gaining electrons (oilrig) Rig: reduction = gaining: source of energy: to build biological molecules. Energy to form bonds could come from: Other forms of natural activity: presence of chemical building blocks. Atmosphere contained harmful gases but at least the molecules were present. Several models of how life started: time for molecules to react with one another. Iron-sulfur world hypothesis (undersea vents: prebiotic soup hypothesis (oparin-haldane) Hypothesis: life formed near earth"s surface + conditions of early earth favored spontaneity. Experiment in 1953: simulated early conditions of earth. Formed amino acids + other organic molecules. Recent development atmosphere may have been neutral and not reducing. Hypothesis: life formed at cracks of ocean floor hydrothermal vents.
