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ESSENTIAL CELL BIOLOGY, FIFTH EDITION
Y Y Y Y
CHAPTER 1: CELLS: THE FUNDAMENTAL UNITS OF LIFE
Y Y Y Y Y Y Y
Unity and Diversity of Cells
Y Y Y Y
1-1 LivingYsystemsYareYincrediblyYdiverseYinYsize,Yshape,Yenvironment,YandYbehavior.YItYisYestimatedYthatY
thereYareYbetweenY10YmillionYandY100YmillionYdifferentYspecies.YDespiteYthisYwideYvarietyYofYorganis
ms,YitYremainsYdifficultYtoYdefineYwhatYitYmeansYtoYsayYsomethingYisYalive.YWhichYofYtheYfollowingYca
nYbeYdescribedYasYtheYsmallestYlivingYunit?
(a) DNAY(b) cell
(c) organelle
(d) protein
1-2 IndicateYwhetherYtheYfollowingYstatementsYareYtrueYorYfalse.YIfYtheYstatementYisYfalse,YexplainYwhy
YitY
isYfalse.
A. TheYParameciumYisYaYmulticellularYmicroorganismYcoveredYwithYhairlikeYcilia.
B. CellsYofYdifferentYtypesYcanYhaveYdifferentYchemicalYrequirements.YC.
TheYbranchlikeYextensionsYthatYsproutYfromYaYsingleYnerveYcellYinYa
mammalianYbrainYcanYextendYoverYseveralYhundredYmicrometers.
1-3 ForYeachYofYtheYfollowingYsentences,YfillYinYtheYblanksYwithYtheYbestYwordYorYphraseYselectedYfromYt
heYlistYbelow.YNotYallYwordsYorYphrasesYwillYbeYused;YeachYwordYorYphraseYshouldYbeYusedYonlyYonc
e.
CellsYcanYbeYveryYdiverse:Ysuperficially,YtheyYcomeYinYvariousYsizes,YrangingYfromYbacter
ialYcellsYsuchYasYLactobacillus,YwhichYisYaYfew
Y
inYlength,YtoYlargerYcellsYsuchYasYaYfrog’sYegg,YwhichYhasYaYdiameterYofY
aboutYone
.YDespiteYtheYdiversity,YcellsYresembleYeachYotherYtoYanYastonishingYdegr
eeYinYtheirYchemistry.YForYexample,YtheYsameY20
areYusedYtoYmakeYproteins.YSimilarly,YtheYgeneticYinformationYofYallYcells
YisYstoredYinYtheir
Y .YAlthough
containYtheYsameYtypesYofYmoleculesYasYcells,YtheirYinabilityYtoYreproduc
eYthemselvesYbyYtheirYownYeffortsYmeansYthatYtheyYareYnotYconsideredYlivingYmatter.
aminoYacids micrometer(s) viruses
DNA millimeter(s)Y yeast
fattyYacids plants
meter
Y plasmaYmembranes
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1-4 HowYdoesYcellularYspecializationYserveYmulticellularYorganismsYandYhowYmightY
aYhighYdegreeYofYspecializationYbeYdetrimental?
1-5 TheYflowYofYgeneticYinformationYisYcontrolledYbyYaYseriesYofYbiochemicalYreactio
nsYthatYresultYinYtheYproductionYofYproteins,YeachYwithYitsYownYspecificYorderYofYa
minoYacids.YChooseYtheYcorrectYseriesYofYbiochemicalYreactionsYfromYtheYoptionsY
presentedYhere.
(a) replication,Ytranscription,Ytranslation
(b) replication,Ytranslation,Ytranscription
(c) translation,Ytranscription,Yreplication
(d) translation,Yreplication,Ytranscription
1-6 ProteinsYareYimportantYarchitecturalYandYcatalyticYcomponentsYwithinYtheYcell,Yhel
pingYtoYdetermineYitsYchemistry,YitsYshape,YandYitsYabilityYtoYrespondYtoYchangesYi
nYtheYenvironment.YRemarkably,YallYofYtheYdifferentYproteinsYinYaYcellYareYmadeYfr
omYtheYsameY20
.YByYlinkingYthemYinYdifferentYsequences,YtheYcellYc
anYmakeYproteinYmoleculesYwithYdifferentYconformationsYandYsurfaceYchemistries,Y
andYthereforeYdifferentYfunctions.
(a) nucleotides.
(b) sugars.
(c) aminoYacids.
(d) fattyYacids.
1-7 WhichYstatementYisYNOTYtrueYaboutYmutations?
(a) AYmutationYisYaYchangeYinYtheYDNAYthatYcanYgenerateYoffspringYlessYfitYf
orYsurvivalYthanYtheirYparents.
(b) AYmutationYcanYbeYaYresultYofYimperfectYDNAYduplication.
(c) AYmutationYisYaYresultYofYsexualYreproduction.
(d) AYmutationYisYaYchangeYinYtheYDNAYthatYcanYgenerateYoffspringYthatYareY
asYfitYforYsurvivalYasYtheirYparentsYare.
1-8 ChangesYinYDNAYsequenceYfromYoneYgenerationYtoYtheYnextYmayYresultYinYoffspri
ngYthatYareYalteredYinYfitnessYcomparedYwithYtheirYparents.YTheYprocessYofYchangeY
andYselectionYoverYtheYcourseYofYmanyYgenerationsYisYtheYbasisYof .
(a) mutation.
(b) evolution.
(c) heredity.
(d) reproduction.
1-9 SelectYtheYoptionYthatYbestYfinishesYtheYfollowingYstatement:Y“EvolutionYis
YaY
process .”
(a) thatYcanYbeYunderstoodYbasedYonYtheYprinciplesYofYmutationYandYselection.
(b) thatYresultsYfromYrepeatedYcyclesYofYadaptationYoverYbillionsYofYyears.
(c) byYwhichYallYpresent-dayYcellsYaroseYfromY4–5YdifferentYancestralYcells.
(d) thatYrequiresYhundredsYofYthousandsYofYyears.
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1-10 SelectYtheYoptionYthatYcorrectlyYfinishesYtheYfollowingYstatement:Y“AYcell’sYgenome
Y .”
(a) isYdefinedYasYallYtheYgenesYbeingYusedYtoYmakeYprotein.
(b) containsYallYofYaYcell’sYDNA.
(c) constantlyYchanges,YdependingYuponYtheYcell’sYenvironment.
(d) isYalteredYduringYembryonicYdevelopment.
Cells Under the Microscope
Y Y Y
1-11 WhichYstatementYisYNOTYtrueYaboutYtheYevents/conclusionsYfromYstudiesYdurin
gYtheYmid-1800sYsurroundingYtheYdiscoveryYofYcells?
(a) CellsYcameYtoYbeYknownYasYtheYsmallestYuniversalYbuildingYblockYofYlivi
ngYorganisms.
(b) ScientistsYcameYtoYtheYconclusionYthatYnewYcellsYcanYformYspontaneousl
yYfromYtheYremnantsYofYrupturedYcells.
(c) LightYmicroscopyYwasYessentialYinYdemonstratingYtheYcommonalitie
sYbetweenYplantYandYanimalYtissues.
(d) NewYcellsYariseYfromYtheYgrowthYandYdivisionYofYpreviouslyYexistingYcells.
1-12 WhatYunitYofYlengthYwouldYyouYgenerallyYuseYtoYmeasureYaYtypicalYplantYorYanim
alYcell?
(a) centimeters
(b) nanometers
(c) millimeters
(d) micrometers
1-13 MatchYtheYtypeYofYmicroscopyYonYtheYleftYwithYtheYcorrespondingYdescripti
onYprovidedYbelow.YThereYisYoneYbestYmatchYforYeach.
A. confocal
B. transmissionYelectron
C. fluorescence
D. phase-contrast
E. scanningYelectron
F. bright-field
Y
usesYaYlightYmicroscopeYwithYanYopticalYcomponentYtoYtakeYadvantageY
ofYtheYdifferentYrefractiveYindicesYofYlightYpassingYthroughYdifferentYregio
nsYofYtheYcell.
Y
employsYaYlightYmicroscopeYandYrequiresYthatYsamplesYbeYfixedYandYstai
nedYinYorderYtoYrevealYcellularYdetails.
YYYYYYYYYrequiresYtheYuseYofYtwoYsetsYofYfilters.YTheYfirstYfilterYnarrowsYtheYwavelen
gthYrangeYthatYreachesYtheYspecimenYandYtheYsecondYblocksYoutYallYwavele
ngthsYthatYpassYbackYupYtoYtheYeyepieceYexceptYforYthoseYemittedYbyYtheYdy
eYinYtheYsample.
YYYYYYYYYscansYtheYspecimenYwithYaYfocusedYlaserYbeamYtoYobtainYaYseriesYofYtwo-
YdimensionalYopticalYsections,YwhichYcanYbeYusedYtoYreconstructYanYimageY
of
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