生物工程专业英语文档格式.docx

生物工程专业英语文档格式.docx

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Contents

Lesson1WhatisBiotechnology?

Biotechnologyinoneformoranotherhasflourishedsinceprehistorictimes.Whenthefirsthumanbeingsrealizedthattheycouldplanttheirowncropsandbreedtheirownanimals,theylearnedtousebiotechnology.Thediscoverythatfruitjuicesfermentedintowine,orthatmilkcouldbeconvertedintocheeseoryogurt,orthatbeercouldbemadebyfermentingsolutionsofmaltandhopsbeganthestudyofbiotechnology.Whenthefirstbakersfoundthattheycouldmakeasoft,spongybreadratherthanafirm,thincracker,theywereactingasfledglingbiotechnologists.Thefirstanimalbreeders,realizingthatdifferentphysicaltraitscouldbeeithermagnifiedorlostbymatingappropriatepairsofanimals,engagedinthemanipulationsofbiotechnology.

Whatthenisbiotechnology?

Thetermbringstomindmanydifferentthings.Somethinkofdevelopingnewtypesofanimals.Othersdreamofalmostunlimitedsourcesofhumantherapeuticdrugs.Stillothersenvisionthepossibilityofgrowingcropsthataremorenutritiousandnaturallypest-resistanttofeedarapidlygrowingworldpopulation.Thisquestionelicitsalmostasmanyfirst-thoughtresponsesastherearepeopletowhomthequestioncanbeposed.

Initspurestform,theterm"

biotechnology"

referstotheuseoflivingorganismsortheirproductstomodifyhumanhealthandthehumanenvironment.Prehistoricbiotechnologistsdidthisastheyusedyeastcellstoraisebreaddoughandtofermentalcoholicbeverages,andbacterialcellstomakecheesesandyogurtsandastheybredtheirstrong,productiveanimalstomakeevenstrongerandmoreproductiveoffspring.

Throughouthumanhistory,wehavelearnedagreatdealaboutthedifferentorganismsthatourancestorsusedsoeffectively.Themarkedincreaseinourunderstandingoftheseorganismsandtheircellproductsgainsustheabilitytocontrolthemanyfunctionsofvariouscellsandorganisms.UsingthetechniquesofgenesplicingandrecombinantDNAtechnology,wecannowactuallycombinethegeneticelementsoftwoormorelivingcells.FunctioninglengthsofDNAcanbetakenfromoneorganismandplacedintothecellsofanotherorganism.Asaresult,forexample,wecancausebacterialcellstoproducehumanmolecules.Cowscanproducemoremilkforthesameamountoffeed.Andwecansynthesizetherapeuticmoleculesthathaveneverbeforeexisted.

Lesson2WhereDidBiotechnologyBegin?

WiththeBasics

Certainpracticesthatwewouldnowclassifyasapplicationsofbiotechnologyhavebeeninusesinceman'

searliestdays.Nearly10,000yearsago,ourancestorswereproducingwine,beer,andbreadbyusingfermentation,anaturalprocessinwhichthebiologicalactivityofone-celledorganismsplaysacriticalrole.

Infermentation,microorganismssuchasbacteria,yeasts,andmoldsaremixedwithingredientsthatprovidethemwithfood.Astheydigestthisfood,theorganismsproducetwocriticalby-products,carbondioxidegasandalcohol.

Inbeermaking,yeastcellsbreakdownstarchandsugar（presentincerealgrains）toformalcohol;

thefroth,orhead,ofthebeerresultsfromthecarbondioxidegasthatthecellsproduce.Insimpleterms,thelivingcellsrearrangechemicalelementstoformnewproductsthattheyneedtoliveandreproduce.Byhappycoincidence,intheprocessofdoingso,theyhelpmakeapopularbeverage.

Breadbakingisalsodependentontheactionofyeastcells.Thebreaddoughcontainsnutrientsthatthesecellsdigestfortheirownsustenance.Thedigestionprocessgeneratesalcohol（whichcontributestothatwonderfularomaofbakingbread）andcarbondioxidegas（whichmakesthedoughriseandformsthehoneycombtextureofthebakedloaf）.

Discoveryofthefermentationprocessallowedearlypeoplestoproducefoodsbyallowingliveorganismstoactonotheringredients.Butourancestorsalsofoundthat,bymanipulatingtheconditionsunderwhichthefermentationtookplace,theycouldimproveboththequalityandtheyieldoftheingredientsthemselves.

CropImprovement

Althoughplantscienceisarelativelymoderndiscipline,itsfundamentaltechniqueshavebeenappliedthroughouthumanhistory.Whenearlymanwentthroughthecrucialtransitionfromnomadichuntertosettledfarmer,cultivatedcropsbecamevitalforsurvival.Theseprimitivefarmers,althoughignorantofthenaturalprinciplesatwork,foundthattheycouldincreasetheyieldandimprovethetasteofcropsbyselectingseedsfromparticularlydesirableplants.

Farmerslongagonotedthattheycouldimproveeachsucceedingyear'

sharvestbyusingseedfromonlythebestplantsofthecurrentcrop.Plantsthat,forexample,gavethehighestyield,stayedthehealthiestduringperiodsofdroughtordisease,orwereeasiesttoharvesttendedtoproducefuturegenerationswiththesesamecharacteristics.Throughseveralyearsofcarefulseedselection,farmerscouldmaintainandstrengthensuchdesirabletraits.

ThepossibilitiesforimprovingplantsexpandedasaresultofGregorMendel'

sinvestigationsinthemid-1860sofhereditarytraitsinpeas.Oncethegeneticbasisofhereditywasunderstood,thebenefitsofcross-breeding,orhybridization,becameapparent:

plantswithdifferentdesirabletraitscouldbeusedtocultivatealatergenerationthatcombinedthesecharacteristics.

Anunderstandingofthescientificprinciplesbehindfermentationandcropimprovementpracticeshascomeonlyinthelasthundredyears.Buttheearly,crudetechniques,evenwithoutthebenefitofsophisticatedlaboratoriesandautomatedequipment,wereatruepracticeofbiotechnologyguidingnaturalprocessestoimproveman'

sphysicalandeconomicwell-being.

HarnessingMicrobesforHealth

EverystudentofchemistryknowstheshapeofaBuchnerfunnel,buttheymaybeunawarethatthedistinguishedGermanscientistitwasnamedaftermadethevitaldiscovery（in1897）thatenzymesextractedfromyeastareeffectiveinconvertingsugarintoalcohol.Majoroutbreaksofdiseaseinovercrowdedindustrialcitiesledeventuallytotheintroduction,intheearlyyearsofthepresentcentury,oflarge-scalesewagepurificationsystemsbasedonmicrobialactivity.Bythistimeithadprovedpossibletogeneratecertainkeyindustrialchemicals（glycerol,acetone,andbutanol）usingbacteria.

Anothermajorbeneficiallegacyofearly20thcenturybiotechnologywasthediscoverybyAlexanderFleming（in1928）ofpenicillin,anantibioticderivedfromthemoldPenicillium.Large-scaleproductionofpenicillinwasachievedinthe1940s.However,therevolutioninunderstandingthechemicalbasisofcellfunctionthatstemmedfromthepost-waremergenceofmolecularbiologywasstilltocome.Itwasthisexcitingphaseofbiosciencethatledtotherecentexplosivedevelopmentofbiotechnology.

Lesson3BriefHistoryofBiotechnology

Biotechnologyseemstobeleadingasuddennewbiologicalrevolution.Ithasbroughtustothebrinkofaworldof"

engineered"

productsthatarebasedinthenaturalworldratherthanonchemicalandindustrialprocesses.

Biotechnologyhasbeendescribedas"

Janus-faced."

Thisimpliesthattherearetwosides.Onone,techniquesallowDNAtobemanipulatedtomovegenesfromoneorganismtoanother.Ontheother,itinvolvesrelativelynewtechnologieswhoseconsequencesareuntestedandshouldbemetwithcaution.Theterm"

wascoinedin1919byKarlEreky,anHungarianengineer.Atthattime,thetermmeantallthelinesofworkbywhichproductsareproducedfromrawmaterialswiththeaidoflivingorganisms.Erekyenvisionedabiochemicalagesimilartothestoneandironages.

AcommonmisconceptionamongteachersisthethoughtthatbiotechnologyincludesonlyDNAandgeneticengineering.Tokeepstudentsabreastofcurrentknowledge,teacherssometimeshaveemphasizedthetechniquesofDNAscienceasthe"

end-and-all"

ofbiotechnology.Thistrendhasalsoledtoamisunderstandinginthegeneralpopulation.BiotechnologyisNOTnew.Manhasbeenmanipulatinglivingthingstosolveproblemsandimprovehiswayoflifeformillennia.Earlyagricultureconcentratedonproducingfood.Plantsandanimalswereselectivelybred,andmicroorganismswereusedtomakefooditemssuchasbeverages,cheese,andbread.

Thelateeighteenthcenturyandthebeginningofthenineteenthcenturysawtheadventofvaccinations,croprotationinvolvingleguminouscrops,andanimaldrawnmachinery.Theendofthenineteenthcenturywasamilestoneofbiology.Microorganismswerediscovered,Mendel'

sworkongeneticswasaccomplished,andinstitutesforinvestigatingfermentationandothermicrobialprocesseswereestablishedbyKoch,Pasteur,andLister.

Biotechnologyatthebeginningofthetwentiethcenturybegantobringindustryandagriculturetogether.DuringWorldWarI,fermentationprocessesweredevelopedthatproducedacetonefromstarchandpaintsolventsfortherapidlygrowingautomobileindustry.Workinthe1930swasgearedtowardusingsurplusagriculturalproductstosupplyindustryinsteadofimportsorpetrochemicals.TheadventofWorldWarIIbroughtthemanufactureofpenicillin.Thebiotechnicalfocusmovedtopharmaceuticals.The"

coldwar"

yearsweredominatedbyworkwithmicroorganismsinpreparationforbiologicalwarfare,aswellasantibioticsandfermentationprocesses.

Biotechnologyiscurrentlybeingusedinmanyareasincludingagriculture,bioremediation,foodprocessing,andenergyproduction.DNAfingerprintingisbecomingacommonpracticeinforensics.Similartechniqueswereusedrecentlytoid