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1、Unit3.BiochemistryandHumanDevelopmentBiochemistryistheapplicationofchemistrytothestudyofbiologicalprocessesatthecellularandmolecularlevel.Itemergedasadistinctdisciplinearoundthebeginningofthe20thcenturywhenscientistscombinedchemistry,physiologyandbiol
2、ogytoinvestigatethechemistryoflivingsystems.Inasense,biochemistryisbothalifescienceandachemicalscience.Itusesthemethodsofchemistry,physics;molecularbiologyandimmunologytostudythestructureandbehaviorofthecomplexmoleculesfoundinbiologicalmaterialandthew
3、aysthosemoleculesinteracttoformcells,tissuesandwholeorganism.Itcoversabroadrangeofcellularfunctionsfromgenetranscriptiontothestructureandfunctionofmacromolecules.生物化学是在细胞和分子水平上运用化学技术研究生物过程的科学。在20世纪初，当科学家联合化学,生理学和生物化学研究的生命系统时，开始出现这门独立学科。在某种意义上说，生物化学既是生
4、命科学又是化学科学，它使用化学、物理学、分子生物学和免疫学方法研究在生物物质中发现的复杂分子结构与行为以及这些分子相互作用构成细胞、组织和整个生物体的方法。它涉及从基因移录到高分子结构和功能的广阔的细胞功能范围。Biochemistryhasbecomethefoundationforunderstandingallbiologicalprocesses;ithasprovidedexplanationsforthecausesofmanydiseasesinhumans,animals,andp
5、lants.Ourunderstandingofbiochemistryhashadandwillcontinuetohaveextensiveeffectsonmanyaspectsofhumanendeavor.First,biochemistryisanintrinsicallybeautifulandfascinatingbodyofknowledge.Wenowknowtheessenceandmanyofthedetailsthemostfundamentalprocessesinbi
6、ochemistry,suchashowasinglemoleculeofDNAreplicatetogeneratetwoidenticalcopiesofitselfandhowthesequenceofthebasesinaDNAmoleculedeterminesthesequenceofaminoacidsinanencodedprotein.Ourabilitytodescribetheseprocessesindetailed,mechanistictermsplacesafirmc
7、hemicalfoundationunderotherbiologicalsciences.Moreover,therealizationthatwecanunderstandessentiallifeprocesses,suchasthetransmissionofheredityinformationaschemicalstructuresandtheirreactionshassignificantphilosophicalimplications.Whatdoesitmean,bioche
8、mically,tobehuman?Whatarethebiochemicaldifferencesbetweenahumanbeing,achimpanzee,amouse,afruitfly?Arewemoresimilarthanwearedifferent?生物化学已成为理解所有生物过程的基础;它提供了对人类、动物和植物许多疾病病因的解释。我们对生物化学的理解已经并将继续在人类努力的许多方面有广泛的影响。首先,生物化学在内在上是一个美丽而迷人的知识体系。我们现在已经知道最基
