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1、Chapter3:TheChemistryofOrganicMolecules3.1OrganicMoleculesA.Definitions1.Mostcommonelementsinlivingthingsarecarbon,hydrogen,nitrogen,andoxygen.2.Thesefourelementsconstituteabout95%ofyourbodyweight.3.Chemistryofcarbonallowstheformationofanenormousvarietyoforganicmolecules.4
2、.Organicmoleculeshavecarbonbondedtootheratomsanddeterminestructureandfunctionoflivingthings.5.Inorganicmoleculesdonotcontaincarbonandhydrogentogether;inorganicmolecules(e.g.,NaCl)canplayimportantrolesinlivingthings.B.CarbonSkeletonsandFunctionalGroups1.Carbonhasfourelectro
3、nsinoutershell;bondswithuptofourotheratoms(usuallyH,O,N,oranotherC).2.Abilityofcarbontobondtoitselfmakespossiblecarbonchainsandrings;thesestructuresserveasthebackbonesoforganicmolecules.3.Functionalgroupsareclustersofatomswithcharacteristicstructureandfunctions.a.Polarmole
4、cules(with+/-charges)areattractedtowatermoleculesandarehydrophilic.b.Nonpolarmoleculesarerepelledbywateranddonotdissolveinwater;thesearehydrophobic.c.Hydrocarbonishydrophobicexceptwhenithasanattachedionizedfunctionalgroupsuchascarboxyl(acid)(--COOH);thenmoleculeishydrophil
5、ic.d.Cellsare70-90%water;thedegreeorganicmoleculesinteractwithwateraffectstheirfunction.4.Isomersaremoleculeswithidenticalmolecularformulasbutdifferinarrangementoftheiratoms(e.g.,glyceraldehydeanddihydroxyacetone).C.BuildingPolymers1.Fourclassesofmacromolecules(polysacchar
6、ides,triglycerides,polypeptides,andnucleicacids)providegreatdiversity.2.Smallorganicmolecules(e.g.,monosaccharides,glycerolandfattyacid,aminoacids,andnucleotides)serveasmonomers,thesubunitsofpolymers.3.Polymersarethelargemacromoleculescomposedofthreetomillionsofmonomersubu
7、nits.D.CondensationandHydrolysis1.Macromoleculesandlargepolymermolecules.2.Macromoleculesbuildbydifferentbondingofdifferentmonomers;mechanismofjoiningandbreakingthesebondsiscondensationandhydrolysis.3.Cellularenzymescarryoutcondensationandhydrolysisofpolymers.4.Duringconde
8、nsationsynthesis,awaterisremoved(condensation)andabondismade(synthesis).a.Whentwomonomers