journal article reagent dehydration dna molecule living organisms Organic krebs cycle carbons organic solvents exothermic reaction hydrogen peroxide electron acceptor substrates synthesis sodium carbon atoms carbon dioxide proteins cesium correlation heat flow catalytic hydrogenation molecules cells molecule alcohols junior chemistry derivatives alkenes chirality local anesthetic hydrogen organic reactions atoms electrophile cis covalent bonds equilibrium temperatures ketone nucleophile acetone isomer atomic mass highest energy salicylic acid constituents phosphate single step hydrogen bonds atom byproducts activation energy intermediates concentration reactants atomic weights glucose alcohol protons reagents solvent cytosine room temperature electron density methanol catalyst joules racemic mixture ethers aspirin chromosomes transition state ammonia chemistry acyl chemicals water molecules electrons acids and bases electron pair amino acids alkene pyruvate thymine esters chemical reactions protons neutrons and electrons metabolism cell cycles alkyne catalysts oxidation organic chemistry hydrogen gas selectivity chemical reaction dehydration reaction presence diels alder reaction