QBM EXAM 1 with correct answers

QBM EXAM 1 bn bn




DefinebnrecombinantbnDNAbntechnology
Usingbnmolecularbnbiologybntechniquesbnsuchbnasbncloning,bnPCR,bnrestrictionbnenzymesbndigestion,bna
ndbngelbnelectrophoresisbntobntakebnabngenebnfrombnonebnsourcebnjoiningbnitbnwithbnanotherbnpiecebnofbnDNA,bncr
eatingbnabnnewbnrecombinantbnDNAbnmoleculebnthatbncanbnbebninsertedbnintobnbacteriabn(orbnotherbnhost)bnandbn
furtherbnstudied.

NamebnthreebncharacteristicsbnofbnDNAbnDoublebnstranded 5'bn->bn3'bndirectionality

Antiparallel

Basebnpairingbn(AT,bnGC)bnviabnhydrogenbnbonding

Whatbnisbnthebncentralbndogmabnofbnmolecularbnbiology? Informationbnisbnonlybnwrittenbninbnonebndirection

DNAbnencodesbnRNAbn(throughbntranscription)bnwhichbnencodesbnproteinbn(throughbntranslation)

Describebnanbnaminobnacid.bnWhatbnisbnmeantbnwhenbnonebnsaysbnproteinsbnarebntranslatedbn"NbntobnC"?
Anbnaminobnacidbnconsistsbnofbnanbnamino-terminus,bnanbna-
carbonbnwithbnanbnRbngroupbn(variable,bn20bntotal),bnandbnabncarboxyl-terminus.

Proteinsbnarebnsynthesizedbnbybnthebnribosomebn"NbntobnC"bnwhichbnmeansbnthatbnthebnfirstbnofbnaminobnacidbn(m
ethionine)bnwillbnhavebnabnfreebnN-
terminus,bnandbnitsbncarboxylbngroupbnwillbnformbnabnpeptidebnbondbnwithbnthebnaminobngroupsbnofbnthebnnextbna
minobnacid.bnThebnendbnofbnthebnproteinbnwillbnhavebnabnfreebnC-terminus.

Describebnthebnfourbnlevelsbnofbnproteinbnstructure Primarybn(aminobnacidbnsequence)

Secondarybn(a-helicesbnandbnB-pleatedbnsheets)bnTertiarybn(overallbn3-dimensionalbnfoldedbnstructure)

Quaternarybn(multiplebnpolypeptidebnchainsbninteracting)

WhenbnviewingbnabnDNAbnorbnproteinbnstructure,bnwhichbnofbnthebnfollowingbnbestbnrepresentsbnwhatbnitbnwould
bnlookbnlikebnifbnyoubncouldbn"seebnit"? Molecularbnsurfacebn(solve-accessiblebnsurface)

Whichbnbranchbnofbngovernmentbnoverseesbnworkplacebnsafety?
OccupationalbnSafetybnandbnHealthbnAdministrationbn(OSHA)

WhatbnisbnanbnMSDSbnandbnwhatbntypebnofbninformationbnwouldbnitbnhave? MaterialbnSafetybnDatabnSheetbn-
bnitbncontainsbnallbnofbnthebninformationbnaboutbnabnchemicalbn(storage,bnhealthbnwarnings,bnsafetybnmeasures,bn

PPE<bnproperbndisposal,flammability,bnwhatbntobndobnifbncontactedbnorbnswallowed,bnetc...)

ThebnQBMbnandbnMicrobiologybnlabsbnatbnUCFbnarebnBSLbn_____. BSL-2

Rankbnthebnfollowingbninbnorderbnofbnoverallbnfitbnasbnwellbnasbnmostbntobnleastbnprotectionbnfrombnchemicalsbnan
dbnpathogens:bnplasticbngloves,bnnobngloves,bnnitrilebngloves,bnlatexbngloves.
Whybnarebnnitrilebnglovesbnoftenbnpreferredbntobnlatexbngloves?

,Latexbnglovesbnofferbnthebnbestbnfirbnandbnprotection,bnfollowedbnbybnnitrilebngloves,bnfollowedbnbybnplasticbnglov
es,bnandbnnobngloves.

Nitrilebnglovesbnarebnoftenbnpreferredbnbecausebnpeoplebnwithbnlatexbnallergiesbncanbnusebnthem.

Namebnthreebntypesbnofbnhazardsbnyoubnmightbnseebninbnabnlaboratory
Biological,bnchemical,bnmechanical

TruebnorbnFalse:bnNeedlesbnshouldbnbebnrecappedbnandbnplacedbninbnthebnsharpsbncontainer
False,bnneedlesbnshouldbnneverbnbebnrecappedbnasbnthisbncanbnleadbntobnanbnaccidentalbnstick.bnTheybnsh
ouldbnalwaysbnbebndiscardedbndirectlybninbnabnsharpsbncontainer.

Whatbntoolbnwouldbnyoubnusebntobnmeasurebnandbntransferbneachbnofbnthebnfollowingbnvolumes?

15bnul:bn

15bnml:bn

150bnml: 15bnul:bnmicropipette

15bnml:bnmechanicalbnpipettorbn(Easypet)bn150bnml:bnGraduatedbncylinder

TruebnofbnFalse:bnWhenbndispensingbnliquidbnfrombnthebnmicropipettebnyoubnshouldbnpushbndownbntobnthebnfirstbn
stop.
False:bnPipettesbnshouldbnbebndispensedbnbybnpushingbndownbntobnthebnsecondbnstopbntobnfullybnexpelbna
nybnliquidbnremainingbninbnthebntip.

Whatbnisbnthebndifferencebnbetweenbnpreparativebnandbnanalyticalbncentrifugation?
Preparativebncentrifugationbnisbnforbnthebnpreparationbnofbnlargebnamountsbnofbnmaterialbn(proteinsbnfo
rbnpurification,bnbacteriabnforbnlysing).bnAnalyticalbncentrifugationbninvolvesbnsmallerbnsamplebnamountsbnandbn
allowsbnonebntobndeterminebnsamplebnpurity,bnmolecularbnweight,bnequilibriumbnconstant,bnthermodynamics,b
netc...



Forbnabnquickbnspindownbnyoubnshouldbnusebnabn______. Smallbnbenchtopbncentrifuge

Whybnarebncentrifugesbnusuallybnrefrigerated?
Tobnpreventbnproteinbndenaturationbnthatbncanbnoccurbnatbnroombntemperature

Whichbntypebnofbnrotorbnisbnbestbnforbnpelletingbnabnsample? Fixedbnanglebnrotor

Whybnaren'tbnallbncentrifugationbnbottlesbnclear?
Clearbnbottlesbnarebnlessbnresistantbntobnchemicalsbnandbnstress

Whatbnisbnthebndifferencebnbetweenbnspectroscopybnandbnspectrometry?
Spectroscopybnisbnthebnseparationbnofbnlightbnintobnitsbnwavelengths

SpectrometrybnisbnthebnmeasurementbnofbnlightbnasbnitbninteractsbnwithbnmatterbnsuchbnasbnDNAbnandbnproteins

Whybndobnresearchersbnoftenbnchoosebntobnusebncolorimetrybnoverbnspectrometry?
Colorimetrybninvolvesbnconvertingbnabnsamplebn(usuallybnprotein)bnintobnabncoloredbncompound.bnThisb
nallowsbnthebnmeasurementbnofbnthebnsamplebnatbnotherbnwavelengthsbn(suchbnasbn595bnorbn750)bnthatbnwon'tbnb

, ebnaffectedbnbybnDNAbnabsorbancebnifbnthebnsamplebnisbnimpure.bnThesebnwavelengthsbnalsobndobnnotbnrequirebns
pecialbnquartzbnorbnUVbncompatiblebncuvettes.

Whichbnpartbnofbnthebnspectrophotometerbnselectsbnlightbnofbnabnspecificbnwavelength?
Monochromator

Howbndoesbntransmittancebndifferbnfrombnabsorbance?
Transmittancebnisbnthebnamountbnofbnlightbnthatbnpassesbnthroughbnabnsample

Absorbancebnisbnthebnamountbnofbnlightbnabsorbedbnbybnabnsample

TransmittancebnandbnabsorbancebnarebnrelatedbnbybnBeer'sbnLaw

Abnsamplebnhasbnabntransmittancebnofbn70%,bnwhatbnisbnit'sbnabsorbance? -log(0.7)bn=bn0.155bnabsorbance

Howbndobnplatebnreadersbndifferbnfrombnspectrophotometers?
Platebnreadersbnarebnessentiallybnspectrophotometersbnthatbnusebn96bnwellbnplatesbntobnmeasurebnmult
iplebnsamplesbnatbnthebnsamebntime.

DNAbnabsorbsbnatbnvariousbnwavelengths,bnwhybnisbn260nmbnusedbnforbnDNAbnquantification?
DNAbnhasbnabnmaximumbnabsorbancebnpeakbnatbn260nm

Abnsamplebnhasbnanbnabsorbancebnofbn0.75,bnwhatbnisbnit'sbntransmittance? 10-
0.75bn=bn0.177bn=bn17%bntransmittance

Abnsamplebngivesbnanbnabsorbancebnofbn0.35bnandbnhasbnanbnextinctionbncoefficientbnofbn40,000.bnWhatbnisbnthebn
concentrationbninbnmicromolar? Abn=bn∈bc

0.35bn=bn(40,000)(1)(c)

cbn=bn8.75bnxbn10-6bnM,bnorbn8.75bnuM

Youbndeterminebnthatbnthebncuvettebnyoubnusedbntobntestbnthebnmixedbnsolutionbnwasbndefective,bnandbnwasbnact
uallybn11mmbninbnwidth.bnWouldbnthebncorrectedbnabsorbancebn(ifbnrecheckedbninbnabnproperbncuvette)bnbebngre
aterbnthanbnorbnlesserbnthanbnthebnabovebnabsorbance?bnWhy?
Ifbnthebncuvettebnpathbnlengthbnwasbn11mmbn(orbn1.1bncm),it'sbnabsorbancebnwouldbnbebnerroneouslybnh
igh,bnsobnifbnyoubnrecheckedbnthebnsolutionbninbnabnproperbncuvettebnitbnwouldbngivebnabnlowerbnabsorbance.

Thebndefectivebncuvettebnwouldbnhavebnplacebnmorebnsolutionbninbnthebnlightbnpathbnthanbnshouldbnhavebnbeen,bn
whichbnwouldbnabsorbbnmorebnlightbnandbngivebnabnhigherbnreadingbnthanbnexpected

YoubnpurifybnabnsamplebnofbnDNAbnandbnpipettebn10bnmicrolitersbnofbnthebnDNAbnintobn90bnmicrolitersbnofbnwaterbn
andbnmeasurebnthisbnsamplebninbnabnspectrophotometer,bnwhichbngivesbnanbnabsorbancebnofbn0.25.bnWhatbnisbnt
hebnconcentrationbnofbnDNAbninbnthebnoriginalbnsample?
A260bn1.0bn=bn50bnugbnofbnDNAbn50(0.25)bn=bn12.5bnug/ml

Dilutionbnfactorbnofbn10X,bnthusbnconcentrationbnisbnequalbntobn125bnug/ml

AbnsamplebnofbnDNAbnhasbnanbnA260:A280bnrationbnofbn1.0.bnIsbnitbnsufficientlybnpure?
No,bntherebnisbnproteinbncontamination.bnThebnA260:A280bnratiobnmuchbnbebn>1.5bnforbnabnsamplebntobn
bebnsufficientlybnpure.