Cyanide and friends: The molecules at the rootHow “complex” organic molecules formThe basic building blocks (all are easily made)Building larger, “biological” molecules: Condensation and (hydrolytic decay)Violation of Second Law of Thermodynamics?Pumping more fuel into the system: ThioestersThe resultant increase in entropy of the Universe leads to assembly of (bio)polymers:Theory: The RNA World (only speculation)Driving force of evolution: Darwinian chemistry – Replication, Mutation, SelectionReplicationMutationSelectionCHEM 451 1st Edition Lecture 1 Outline of Last Lecture I. Syllabus and Course Expectations Outline of Current Lecture II. The molecules at the rootIII.How “complex” organic molecules formA.Basic building blocksB.Building larger, “biological” moleculesC.Second Law of ThermodynamicsIV. Assembly of biopolymers V. Darwinian Chemistry = Driving force of Evolution: Replication, Mutation, SelectionCurrent LectureCyanide and friends: The molecules at the root- 1953: Stanley L. Miller & Harold C. Urey of University of Chicago conducted the Discharge Experiment- Took simple molecules such as N2, CO2, HCN (toxic, kills our phosphorylation cascade), NH3, H2O, and CH4 and put into reflux system.- Water condenses in glass, heated; water forms condensation cloud exposed to electrical discharge (battery)- When performed for hours/days/weeks….- After a few months, Urey & Miller discovered complex molecules within the flask (as opposed to the simple molecules that they started with)How “complex” organic molecules form- Simple molecules tend to “self-organize” (inorganic to organic)o H2CO + NH3 + H-CN  H2N-CH2-CN (aminonitrile) + water  glycine + ammonia- Many of the simple amino acids were found in the reflux flask of the discharge experiment- These organic molecules closely resemble the same materials found in the Murchison Meteorite.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Suggests that the meteorite flew through space under similar conditions as condensing inorganic molecules in the discharge experiment.o Ample energy was available to condense them- 1961: U. Houston Juan Oro condensed 3 hydrogen cyanide (HCN) molecules, fused with ammonia, and created a heterocycle.o Adenine was produced – nitrogenous building blocko Only two different types of molecules were condensed to produce this stable aromatic compoundThe basic building blocks (all are easily made)- Amino acids- Nucleo bases- Lipids: contain glycerol and fatty acidso Condense CO2 with ethylene molecules to create fatty acids (carboxyl from CO2)- Sugars (carbohydrates)o Formaldehyde is the simplest carbohydrate H2CO = C(H2O)o Continue to add C(H2O) molecules to make larger sugars- 19th century: primordial soup – water condensed with energy to create all these monomeric ingredients of life.Building larger, “biological” molecules: Condensation and (hydrolytic decay)- Biochemical ingredients condense, leading to ejection of water- Water is abundant in earth’s hemisphere – high density liquid (55 M)- More condensation reactions liberate more watero This is a reversible reaction! Water can hydrolyze peptide bonds to liberate 2 amino acids from a peptide bond.o Le Chatelier’s Principle- New theory: Perhaps reactions were not performed in a simple tidal pool of water (earth’s core), but instead occurred near the surface in an abundance of minerals.- Ex) Clay is used to separate molecules in chromatography, etc. Present in the ground; a type of silicao Good for absorbing organic moleculeso Perhaps could absorb amino acids on its surface, using the surface as a catalyst for amino acids to condense togethero Clay could also aid in the reaction by keeping carboxylate unprotonated/ protonated, perhaps acid-base catalysiso Additionally, clay pockets may help exclude water.Violation of Second Law of Thermodynamics?- If there is decay, doesn’t the second law (entropy tends to increase) drive everything back to square one?- This is only true of the universe as a whole. o As long as there is an energy source to drive the condensation reaction, then molecules can keep at a higher energy because entropy has increased somewhere else.o Thus, locally, entropy may decrease.- The second law is not violated.- Types of energy sources that may have been available at the origin of life:o Upper mantle of earth (liquid-metal core, molten rocks) might have contributed energy in the form of heat to allow synthesis of primitive life forms Liquid rock emerging from volcanoes moved to sea-floor sediment Energy was “shuffled” into the systemo Perhaps pyrite (FeS2) contributed energy Extra sulfur in low oxidation can be oxidized to sulfate, intrinsic energy utilized Gunter Wachtershauser: perhaps molecules could be condensed on the surface of iron sulfide minerals, naturally absorbing negatively-charged phosphates on organic compounds by the positive charge of the pyrite Minerals can perform oxidation reactions, creating energy to increase complexityo Additionally, electrical discharge, sun-rays, x-rays could have provided energyPumping more fuel into the system: Thioesters- Thioesters = “alcohol with a sulfur”; may be a connection between pyrite and thioesters via high temperature acidic conditions (thermal vents)- Thioesters are found in many metabolic pathways; may be fossils of origin of lifeThe resultant increase in entropy of the Universe leads to assembly of (bio)polymers:Example: RNA- Take nucleotides, use mineral catalysts to condense them together to create complex biopolymers with initially random sequences- This gave rise to ribonucleic acids, which condensed the building blocks of nitrogenous bases that allowed for information content (DNA replication blueprint)Theory: The RNA World (only speculation)- There is a good chance that early on, RNA molecule arose from early simple condensation that had critical functions and features that we associate with life- RNA: Information-containing molecule; at least one sequence had an ability to self-replicate- Copies by aligning building blocks for complementary sequences, condensing monomerstogether- Once complement present, found a way to separate the complement from the template- This creates a cycle – self-amplication leads to a fit catalyst that can make more of itself, despite degradation from