CELL BIOLOGY EXAM 3 HOMEWORK AND CLICKER QUESTIONS AND CORRECT ANSWERS

CELL BIOLOGY EXAM 3 HOMEWORK
AND CLICKER QUESTIONS AND
CORRECT ANSWERS
TheA2lipidA2componentsA2ofA2cellularA2membranesA2includeA2-A2Ans--
cholesterolA2andA2phospholipids

WhichA2typeA2ofA2lipidsA2areA2theA2mostA2abundantA2inA2theA2plasmaA2membrane?A2-
A2Ans--phospholipids


IntegralA2membraneA2proteinsA2areA2proteinsA2thatA2-A2Ans--
partiallyA2penetrateA2orA2completelyA2spanA2theA2phospholipidA2bilayerA2ofA2theA2membra
ne.

WhichA2ofA2theA2followingA2preventsA2theA2freeA2passageA2ofA2mostA2substancesA2acrossA
2aA2biologicalA2membrane?A2-A2Ans--theA2hydrophobicA2coreA2ofA2theA2lipidA2bilayer


WhichA2ofA2theA2followingA2functionsA2ofA2theA2plasmaA2membraneA2isA2possibleA2withoutA
2membraneA2proteins?A2-A2Ans--selectiveA2permeability


WhichA2ofA2theA2followingA2describesA2aA2saturatedA2triglyceride?A2-A2Ans--
ThereA2areA2noA2doubleA2bondsA2presentA2betweenA2carbonA2atomsA2inA2theA2fatA2molecu
le.

WhichA2ofA2theA2followingA2statementsA2isA2trueA2concerningA2membraneA2fluidity?A2-
A2Ans--
decreasedA2fattyA2acidA2sideA2chainA2saturationA2andA2increasedA2temperatureA2increaseA
2membraneA2fluidity


WhichA2ofA2theA2followingA2isA2trueA2ofA2integralA2membraneA2proteins?A2-A2Ans--
TheyA2areA2usuallyA2transmembraneA2proteins.

HowA2doA2unsaturatedA2fattyA2acidsA2helpA2keepA2anyA2membraneA2moreA2fluidA2atA2lower
A2temperatures?A2-A2Ans--
TheA2doubleA2bondsA2formA2kinksA2inA2theA2fattyA2acidA2tailsA2thatA2preventA2adjacentA2lipi
dsA2fromA2packingA2tightlyA2together.

CellA2membranesA2inA2plantsA2thatA2thriveA2inA2extremeA2coldA2areA2ableA2toA2remainA2flui
dA2byA2-A2Ans--
decreasingA2theA2percentageA2ofA2saturatedA2phospholipidsA2inA2theA2membrane.

, WhichA2ofA2theA2followingA2evolutionaryA2adaptationsA2wouldA2youA2expectA2toA2findA2inA2t
heA2cellA2membranesA2ofA2AntarcticA2icefish?A2-A2Ans--
aA2highA2percentageA2ofA2unsaturatedA2fattyA2acids

WhatA2kindsA2ofA2moleculesA2passA2throughA2aA2cellA2membraneA2mostA2easily?A2-A2Ans--
smallA2hydrophobic

WhichA2ofA2theA2followingA2moleculesA2wouldA2youA2expectA2toA2diffuseA2throughA2theA2lipi
dA2bilayerA2ofA2aA2plasmaA2membraneA2mostA2rapidly?A2-A2Ans--O2

WhichA2ofA2theA2followingA2statementsA2aboutA2netA2diffusionA2isA2correct?A2-A2Ans--
ItA2isA2aA2passiveA2processA2inA2whichA2moleculesA2moveA2fromA2aA2regionA2ofA2higherA2co
ncentrationA2toA2aA2regionA2ofA2lowerA2concentration.

CarrotA2slicesA2placedA2inA2aA20.2A2MA2saltA2solutionA2forA2severalA2hoursA2becomeA2flacci
dA2(limp).A2CarrotA2slicesA2placedA2inA2freshA2waterA2forA2severalA2hoursA2becomeA2turgidA
2(stiff).A2FromA2thisA2weA2canA2deduceA2thatA2-A2Ans--
theA2freshA2waterA2isA2hypotonicA2andA2theA2saltA2solutionA2isA2hypertonicA2toA2theA2cellsA2
ofA2theA2carrotA2slices.

InA2responseA2toA2seasonalA2changesA2inA2temperature,A2manyA2organismsA2mustA2alterA
2theA2compositionA2ofA2theirA2plasmaA2membranesA2toA2maintainA2theA2properA2degreeA2o
fA2fluidity.A2AsA2summerA2turnsA2toA2fallA2andA2eventuallyA2intoA2winter,A2whichA2ofA2theA2fo
llowingA2wouldA2youA2predictA2youA2wouldA2observeA2inA2theA2plasmaA2membranesA2ofA2o
rganismsA2thatA2areA2unableA2toA2regulateA2theirA2bodyA2temperature?A2-A2Ans--
aA2decreaseA2inA2phospholipidA2fattyA2acidA2sideA2chainA2lengthA2andA2aA2decreaseA2inA2si
deA2chainA2saturation

TheA2aminoA2acidA2sequencesA2belowA2representA2theA2sequencesA2ofA2transmembraneA
2helices.A2TheA2characteristicsA2ofA2αhelicesA2thatA2formA2aA2channelA2areA2differentA2from
A2thoseA2thatA2formA2aA2singleA2transmembraneA2domain.A2SelectA2theA2helixA2thatA2forms
A2aA2singleA2transmembraneA2domain.A2-A2Ans--IMIVLVMLLNIGLAILFVHF


BelowA2isA2aA2listA2ofA2moleculesA2withA2differentA2chemicalA2characteristics.A2KnowingA2t
hatA2allA2moleculesA2willA2eventuallyA2diffuseA2acrossA2aA2phospholipidA2bilayer,A2selectA2t
heA2optionA2belowA2thatA2mostA2accuratelyA2predictsA2theA2relativeA2ratesA2ofA2diffusionA2o
fA2theseA2moleculesA2(fastestA2toA2slowest).A2alanineA2estrogenA2propanolA2sodiumA2-
A2Ans--estrogenA2>propanolA2>alanineA2>sodium


MammalianA2bloodA2containsA2theA2equivalentA2ofA20.15A2MA2NaCl.A2SeawaterA2containsA
2theA2equivalentA2ofA20.45A2MA2NaCl.A2WhatA2willA2happenA2ifA2redA2bloodA2cellsA2areA2tran
sferredA2toA2seawater?A2-A2Ans--
WaterA2willA2leaveA2theA2cells,A2causingA2themA2toA2shrivelA2andA2collapse.

Transporters,A2inA2contrastA2toA2channels,A2workA2byA2-A2Ans--filteringA2solutesA2byA2size.