The Science of Maryland Agriculture

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national origin, marital status, genetic information, political affiliation, or gender identity or expression.

GOAL STATEMENT:• StudentswilllearnthatDNAisthemoleculethatisresponsiblefortheinheritanceoftraitsandwill

understandthatselectivebreedingandgeneticengineeringareusedtodevelopdesiredtraits.

OBJECTIVES: • StudentswilllearnthatDNAisthemoleculeresponsiblefortheinheritanceoftraitsinallorganisms

andunderstandthatDNAisfoundinallofthefoodthatweeat.• StudentswilllearnhowtoextractDNAfromcornandobservewhatlargequantitiesofDNAlookliketo

thenakedeye.• Studentswillunderstandhowselectivebreedingandgeneticengineeringcontributetoanincreased

foodsupplyforpeople.• Studentswilllearnaboutgeneticallymodifiedorganisms(GMOs)inagriculture.

REQUIRED MATERIALS:• 1pairofgoggles• 1zip-styleplasticsandwichbag• 1cone-shaped#2coffeefilter• 15-ounceplasticcup• 1plasticpipette• 15kernelsoffreshsweetcornor10kernelsoffrozensweetcorn

If you want to experiment with other fruits or vegetables, you can substitute the corn for 1 medium-sized strawberry, 12 sweet peas, or ¼ of a medium-sized tomato. Use fresh or frozen foods, not canned.

• 10mlDNAextractionbufferThe teacher will need to prepare this solution in advance. Required ingredients include a clear hair shampoo with EDTA, table salt, and non-chlorinated water. See the “Exploration” section for details and preparation instructions.

• 15mlethanolorpropanol(isopropyl)alcohol,chilled• 20mlGlasstesttubes• 1paperclip• Copyofthe“CornDNAExtractionDataSheet”• Optional:Copyofthe“GeneticallyModifiedOrganismsResearchGuide”fortheExtensionactivity

AMOUNT OF TIME TO ALLOW:40-50minutes.Extensionactivitieswilltakeadditionaltime.

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry,

national origin, marital status, genetic information, political affiliation, or gender identity or expression.

DNA and genes Eachpersonismadeupoftrillionsofmicroscopiccells.Aperson’shandhasmorethan2.5billioncells!

Eachtypeofcellinthebodyhasitsownspecificfunctions,buteverycellalsohasgeneticinformationinitsnucleus(center)thatcodesfortheproductionoftheentireorganism.CellsreceiveinstructionsonhowtoperformtheirfunctionsfromamoleculecalledDNA,ordeoxyribonucleicacid.DNAismadeofmanysubunits,calledgenes,whichcontaininstructionsfortheproductionofdifferenttypesofproteins.Proteinsaremoleculesthatbuildthestructureofanorganismandcontrolavarietyoffunctions.Anorganism’sDNAalsocontrolstheexpressionofphysicalandbehavioraltraitsofthatorganism.TheshapeofDNAissimilartothatofatwistedladderandiscalledadoublehelix.DNAincellsisorganizedintocoiledstructurescalledchromosomes.Differentspecieshavedifferentnumbersofchromosomesintheircells.SinceDNAisinsideofcells,andcellsaremicroscopic,DNAisverytiny.However,whenstudentsextracttheDNAfromthousandsofcellstogether(astheywilldointhislesson),itbecomesvisibletothenakedeye.

DNAcontrolstheinheritanceoftraitsinhumansandallotherlivingorganisms.ThegeneticinformationcontainedinDNAispassedfromparentstooffspring.Inpeople,50%ofeachcell’sDNAcomesfromthemother,and50%comesfromthefather.Everypersonreceivesadifferentcombinationofgenesfromhisorherparents.Siblingsoftenappearsimilarbecausetheysharesomeofthesamegenes.OnlyidenticaltwinshavetheexactsameDNA.

Selective breeding and genetically modified organisms Inagriculture,farmersarealwaystryingtoproduceplantsandanimalswithtraitsthatarethemostdesirable.Toachievethis,farmersuseselective breeding,theprocessofbreedingindividualswithdesiredtraitstoproduceoffspringthatcontainmoreofthosetraits.Itoftentakesmanygenerationstoproducethedesiredresult.Overthepastseveralhundredyears,peoplehavedevelopedmanydifferentvarietiesofplants(forexample,applesareavailableinmanyvarieties)andbreedsofanimalsusingselectivebreeding.

Inrecentyears,scientistshavebegunusinggene mappingtofindoutwhichpartsofanorganism’sDNAcodeforwhichtraits.DNAhasnowbeenmappedformanyagriculturalplantandanimalspecies.Onceaspecies’DNAhasbeenmapped,scientistscanuseaprocesscalledgenetic engineeringtoproduceoffspringwithdesiredtraitsmuchfasterthancanbeachievedthroughselectivebreeding.Ingeneticengineering,scientistsaddorremoveDNAtochangethetraitsanorganismexpresses.Mostfrequently,genesfromoneorganismareremovedandtransferredintoanotherorganism,allowingthatorganismtoexpresstraitsitdidn’tpossessbefore.AnyorganismwhoseDNAhasbeenalteredbyscientists–eitherthroughadditionordeletionofgenes–iscalledagenetically modified organism (GMO).Applications of genetic biotechnologyTherearemorethan7billionpeopleonourplanet,andthatpopulationisgrowingeveryday.However,theamountoflandwehavetoproducefoodtofeedourpopulationislimited.By2050,it’sestimatedthatfarmerswillneedtoproducetwiceasmuchfoodastheyproducetodaytomeettheworld’sdemand.Biotechnologieslikeselectivebreedingandgeneticmodificationcanmakecropsmoreresistanttopressureslikeinsects,diseases,andunfavorableweatherandthusallowfarmerstoproducemorefoodonthesameamountofland.

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry,

national origin, marital status, genetic information, political affiliation, or gender identity or expression.

Teacher’s Note: Be sure to chill the ethanol or isopropyl alcohol prior to the lesson. The DNA extraction buffer should also be mixed before beginning the lesson. In a pint jar or 500 ml beaker, combine the following ingredients:

• 50 ml of a clear hair shampoo with EDTA (ethylenediaminetetraacetic acid), like Suave. Do not use one that contains a conditioner.

• 1 tsp of NaCl (table salt)• 450 mL water (non-chlorinated)

In1960,oneAmericanfarmerfedabout29people.Today,oneAmericanfarmerfeeds155people.Askstudentstopredicthoworwhythischangeoccurred.Leadtheconversationintoadiscussionabouthowbettertechnology,includingbetterplantandanimalgenetics,hasincreasedtheAmericanfarmers’productivity.Herearesomespecificexamplesyoumaycite:

• Dairycowgeneticshaveimproved,largelyduetoselectivebreedingandbetterenvironmentalconditionslikehigherqualityfeedandmorecomfortablehousing.In1960,theaveragedairycowproduced8,000poundofmilkperyear.Todaytheaveragedairycowproduces22,000poundsofmilkperyear.

• In1960,theaverageAmericanfarmerproduced75bushelsofcornperacre.Todaytheaverageisover160bushelsperacre.Theincreaseinyieldisattributedtoimprovedtillagemethods,bettercontrolofweedsusingpesticidetechnology,andimprovedplantgenetics.

Beforemovingintotheexplorationsection,ensurethatstudentshaveanunderstandingofthebasicformandfunctionofDNA.Dependingonthepreviousknowledgeoftheclass,youmayneedtoincludeaconversationonsomeoftheprincipleslistedinthe“BackgroundInformation–DNAandgenes”sectionabove.

ThedevelopmentofGMOshascausedcontroversybecausetheseorganismscontaingenecombinationsthatwerecreatedbypeopleanddon’toccurnaturally.ItisimportanttonotethatallGMOsapprovedforhumanconsumptionarefieldtestedandregulatedintheUnitedStatesbyvariousU.S.governmentagencies.Therearecurrentlyeightgenetically-modifiedcroporganismsthatareapprovedtobegrownintheU.S.:corn,soybeans,cotton,canola,alfalfa,sugarbeets,papaya,andsquash.Thesecropshavebeenmodifiedtoincludegenesthatmakethemmoreresistanttodisease,insects,andpesticides.

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry,

national origin, marital status, genetic information, political affiliation, or gender identity or expression.

We’veallheardthatDNA’sdoublehelixlookslikeatwistedladderonamicroscopiclevel.Butwhatifyoucouldseeitwiththenakedeye?Tellstudentsthatinthisexercisetheywillbebreakingapartcorncells,releasingtheDNAfromthenucleus,andseparatingtheDNAfromtherestofthecell’sstructures.AllofthoseDNAstrandstogetherwillbevisiblewithoutamicroscope!

ShowstudentsadiagramofwhereDNAisfoundinaplantcell.HelptheminterpretthediagramandwhatitshowsaboutDNA.

Havestudentsstarttheexperimentworkingingroupsof2-4dependingonclasssizeandavailablesupplies.

Predict the Appearance of DNA1. Askstudentstocompletequestion#1ofthe“CornDNAExtractionDataSheet”bypredicting

whatDNAwilllooklikeafteritisextractedfromcorncells.Prepare the DNA

2. Haveagrouprepresentativeget15kernelsoffreshsweetcornor10kernelsoffrozensweetcornforthegrouptouse.(Ifyouwanttoexperimentwithotherfruitsorvegetables,youcansubstitutethecornwith1largestrawberry,12sweetpeas,or¼ofamediumsizedtomato.Youmaywanttoassignadifferentfruitorvegetabletoeach

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry,

national origin, marital status, genetic information, political affiliation, or gender identity or expression.

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry,

national origin, marital status, genetic information, political affiliation, or gender identity or expression.

groupandhavegroupscomparetheirresults.)3. Placethecornkernelsinazip-styleplasticsandwichbag,closethebag,andmashthekernels

for1-2minutes.4. Usingapipette,add10mloftheextractionbuffertothebagandclosethebag.5. Mixthesolutionfor1minute.6. Puttheconeshaped#2coffeefilteroverthetopofthe5oz.plasticcupsothatithangsinside

butdoesnottouchthebottomofthecup.7. Pourthesolutionintothefilterandletitdrainintothecupfor10minutes.8. Whilethestudentswaitforthesolutiontodrain,askthemtocompletequestions#2-4onthe

datasheet.

Transfer the DNA extract9. Measure15mlofchilledethanolorisopropylalcoholintoaglasstesttubeorsimilarcontainer.10.Usingthepipette,transfertheextractfromthebottomofthecupintothealcoholinthetest

tube.(Youwillneedtoaddatleast.5mlandupto3mloftheextract.)Oncetheextractisadded,gentlyandslowlyswirlthetubefor2-5seconds.(Donotshakethetube.)

Askthestudentstocompletequestion#5onthedatasheet.

Observe the DNA11.Lookverycloselyatthesolutionandobservefor5-10minutes.

Askthestudentstocompletequestion#6onthedatasheet.

Remove the DNA12.Usingalargepaperclip,removetheDNAfromthetesttubeandobserve.Youmayneedto

bendthepaperclipintoahookshape.

Havethestudentsdiscusswhattheyobservedwithintheirgrouporasaclass.Leadtheconversationintoadiscussionoftheprinciplesofselectivebreeding,genemapping,andgeneticengineering.Youmaywanttorefertothe“BackgroundInformation”sectionabovefordetailsandpointstoincludeinthediscussion.

Havestudentsworkindividuallyoringroupsofuptofourtoresearchgeneticallymodifiedorganisms.Youmayhavethemcompletethe“GeneticallyModifiedOrganismResearchGuide”andprepareapresentationfortheirclassmates.Assignadifferentgeneticallymodifiedcroptoeachgroup.

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry,

national origin, marital status, genetic information, political affiliation, or gender identity or expression.

• Biotechnologist—Scientistthatdevelopsplantsandanimalsthathavebettertraitsandhigheryields.TheyworkatthecellularlevelusingavarietyofmethodstochangethegeneticinformationintheDNA.

• Plant Geneticist—ScientistthatstudiesDNAandhowthesetraitsaffectscharacteristicslikegrowth,productionandreproductiontraitsinplants.

• Plant Pathologist—Scientistthatdealswiththecauses,damage,andcontrolofplantdiseases. • Animal Geneticist—ScientistthatstudiesDNAandhowthesetraitsaffectsphysicaland

behavioraltraitsinanimals. • Animal Pathologist—Scientistthatdealswiththecauses,damageandcontrolofanimal

diseases.

Apre/posttestshouldbecompletedwiththislessonplan.Studentunderstandingofconceptscanalsobeevaluatedthroughclassdiscussionaswellasthroughevaluationofcompletedactivitydatasheets.Analysis/conclusionquestionsthatareansweredincorrectlybyalargenumberofstudentsshouldbeaddressedinafollow-updiscussion.

Module3:StrawberryDNAExtraction,PioneerHi-BredInternational<ucbiotech.org/resources/display/files/dna_extraction_from_strawberrie.pdf>

InnovationinAgriculture:TheplusesofBiotechnologyinCornProduction<www.worldofcorn.com/pdf/ncga-innovation-in-agriculture.pdf>

HowtoExplainDNAtoKids<tfscientist.hubpages.com/hub/explaining-dna-to-a-six-year-old>

GMOAnswers-OctoberisGettoKnowGMOsMonth<gmoanswers.com/studies/october-get-know-gmos-month>

NationalAgricultureStatisticService<www.nass.usda.gov>

The Science of Maryland Agriculture

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, national origin, marital status, genetic information, political affiliation, or gender identity or expression.

Name:

Date: Period:

Corn DNA Extraction Data SheetPredict the Appearance of DNA1.DrawanddescribewhatyouthinkthecornDNAwilllooklikewhenyouextractitfromtheplantcells.

Prepare the DNA2.Whywasitnecessarytomashthecornkernels?

3.Whatisthepurposeoftheextractionsolutionwhichcontainssoap,salt,andwater?

4.Whatisthepurposeofthefilter?

Transfer the DNA extract5.DescribewhathappenstotheDNAsolutionasitisaddedtotheethanol/isopropanolalcohol.

The Science of Maryland Agriculture

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, national origin, marital status, genetic information, political affiliation, or gender identity or expression.

Name:

Date: Period:

Corn DNA Extraction Data SheetPredict the Appearance of DNA6.Afterobservingthemixturefor5-10minutes,drawanddescribewhatyousee.

Remove the DNA7.DrawanddescribewhatyouseeaftertheDNAhasbeenremovedfromthetesttube.

The Science of Maryland Agriculture

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, national origin, marital status, genetic information, political affiliation, or gender identity or expression.

Name:

Date: Period:

TEACHER KEY: Corn DNA Extraction Data Sheet

Predict the Appearance of DNA1.DrawanddescribewhatyouthinkthecornDNAwilllooklikewhenyouextractitfromtheplantcells.SampleAnswers:differentcolors,twistedladder,doublehelix,etc.(answersmayvarydependingonwhatstudentsalreadyknowaboutDNA)

Prepare the DNA2.Whywasitnecessarytomashthecornkernels?Tobreakopenthecells

3.Whatisthepurposeoftheextractionsolutionwhichcontainssoap,salt,andwater?ThesoapandthesaltintheextractionsolutionhelpstoreleaseDNAfromthecells

4.Whatisthepurposeofthefilter?ThefilterhelpstoseparatetheDNAfromthelargepartsofthecornkernel

Transfer the DNA extract5.DescribewhathappenstotheDNAsolutionasitisaddedtotheethanol/isopropanolalcohol.TheDNAbegantosettleandclingtogetheratthebottomofthetesttube

Observe the DNA6.Afterobservingthemixturefor5-10minutes,drawanddescribewhatyousee.TheDNAstandsclingtootherDNAstrandsandformalayerinthetube

Remove the DNA7.DrawanddescribewhatyouseeaftertheDNAhasbeenremovedfromthetesttube.TheDNAlookslikefuzzy,whitethreads,twistedandclumpedtogether

The Science of Maryland Agriculture

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, national origin, marital status, genetic information, political affiliation, or gender identity or expression.

Name:

Date: Period:

Genetically Modified Organisms Research GuideNameofthegeneticallymodifiedorganism:

Whywasitdeveloped?

Whenwasitdeveloped?

Whatmakesitdifferentfromanon-GMOorganism?

Whatarethebenefits?

Whatarethepotentialproblems/concerns?

Listyourreferences:

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, national origin, marital status, genetic information, political affiliation, or gender identity or expression.

The Science of Maryland Agriculture

PRE-Evaluation: Feeding Our Future1.Howoldareyou?______________

3.Areyou….(SelectALLthatapply.) AfricanAmerican/Black Asian Other NativeAmerican/AlaskanNative Hispanic/Latino White NativeHawaiian/OtherPacificIslander

4.Whattypeofschooldoyougoto?(Selectone.) Publicschool Privateschool Religiousschool(Catholic,etc.) Homeschool

2.Areyou...(Selectone.) Aboy Agirl

Your Science and Agriculture Opinions and Knowledge5.BEFORE going through the AGsploration Program,pleasecirclethedegreetowhichyouagreeordisagreewiththefollowingstatements.

6.BEFORE going through the AGsploration Program,pleasecircleyourknowledgelevelaboutthetopicslistedbelow.

StronglyDisagree Disagree Agree Strongly

Agree

Ilikescience. 1 2 3 4

IfeelthatMarylandagricultureisapartofscience. 1 2 3 4

Scienceisusefulforsolvingeverydayproblems. 1 2 3 4

Marylandagricultureisbeneficialtome,myfamily,andmycommunity.

1 2 3 4

WhenIgraduatefromhighschool,Iwouldliketohaveajobinagriculturalscience.

1 2 3 4

Icannamethreejobsintheagricultureindustry. 1 2 3 4

None Low Medium High VeryHigh

MarylandAgriculture 1 2 3 4 5

Inheritance 1 2 3 4 5

DNA 1 2 3 4 5

GeneticallyModifiedOrganism 1 2 3 4 5

FoodProduction 1 2 3 4 5

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, national origin, marital status, genetic information, political affiliation, or gender identity or expression.

The Science of Maryland Agriculture

POST-Evaluation: Feeding Our FutureYour Science and Agriculture Opinions and Knowledge7.AFTER going through the AGsploration Program,pleasecirclethedegreetowhichyouagreeordisagreewiththefollowingstatements.

8.AFTER going through the AGsploration Program,pleasecircleyourknowledgelevelaboutthetopicslistedbelow.

9.Asaresultofparticipatinginthisactivity,tellonenewthingyouwilltryoronethingyouwillfindinformationabout.

StronglyDisagree Disagree Agree Strongly

Agree

Ilikescience. 1 2 3 4

IfeelthatMarylandagricultureisapartofscience. 1 2 3 4

Scienceisusefulforsolvingeverydayproblems. 1 2 3 4

Marylandagricultureisbeneficialtome,myfamily,andmycommunity.

1 2 3 4

WhenIgraduatefromhighschool,Iwouldliketohaveajobinagriculturalscience.

1 2 3 4

Icannamethreejobsintheagricultureindustry. 1 2 3 4

None Low Medium High VeryHigh

MarylandAgriculture 1 2 3 4 5

Inheritance 1 2 3 4 5

DNA 1 2 3 4 5

GeneticallyModifiedOrganism 1 2 3 4 5

FoodProduction 1 2 3 4 5

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, national origin, marital status, genetic information, political affiliation, or gender identity or expression.

The Science of Maryland Agriculture

SUPPLEMENTAL-Evaluation: Feeding Our FutureDirections:Ifyouareteachingmorethanonelessonplaninoneday,youmayattachthistothepre/postevaluationformfortheotherlessonyouareteaching.Pleasehavethestudentfillouttheseduringthepreandpostevaluationtimes.Inaddition,onlyhavethestudentfilloutthepostevaluationquestionsQ5–Q7atthecompletionofalllessons.

PRE-EvaluationBEFORE going through the AGsploration Program,pleasecircleyourknowledgelevelaboutthetopicslistedbelow.

POST-EvaluationAFTER going through the AGsploration Program,pleasecircleyourknowledgelevelaboutthetopicslistedbelow.

None Low Medium High VeryHigh

MarylandAgriculture 1 2 3 4 5

Inheritance 1 2 3 4 5

DNA 1 2 3 4 5

GeneticallyModifiedOrganism 1 2 3 4 5

FoodProduction 1 2 3 4 5

None Low Medium High VeryHigh

MarylandAgriculture 1 2 3 4 5

Inheritance 1 2 3 4 5

DNA 1 2 3 4 5

GeneticallyModifiedOrganism 1 2 3 4 5

FoodProduction 1 2 3 4 5