Proteins and nucleic acids rely on hydrogen bonds forstabilityThymineDNAAdenine5'EnHydrogenbondSide viewCytosine3'EndGuanine5'End
Proteins and nucleic acids rely on hydrogen bonds for stability
Number of hydrogenbondsIn liquid, each H,O molecule formshydrogen bonds with an average of3.4 othermoleculesIn ice, each H,O molecule forms 4hydrogen bondsConstantly forming and breaking(in a dynamic way)BONDS
Number of hydrogen bonds In liquid, each H2O molecule forms hydrogen bonds with an average of 3.4 other molecules In ice, each H2O molecule forms 4 hydrogen bonds Constantly forming and breaking (in a dynamic way)
Properties ofwaterHighlycohesiveH-bondinginteractionsH-bondsOnewatermoleculecanH-bondwith4othersLifetimeontheorderofpicosecondsWatermoleculesinnearlyconstantmotion
Properties of water Highly cohesive • H-bonding interactions • One water molecule can H-bond with 4 others • Lifetime on the order of picoseconds • Water molecules in nearly constant motion
Properties of waterHighly cohesiveSurfacetensionLiquidatroomtemperatureOO.Highsurfacetension(forcedrawingsurfacemoleculesin）
Properties of water Highly cohesive • Liquid at room temperature • High surface tension (force drawing surface molecules in)
Properties ofwaterSolidlessdenseH-bondinginteractionsDirectionalityconfersgeometricconstraint
Properties of water Solid less dense • H-bonding interactions • Directionality confers geometric constraint