2 movement in and out of cells - chaucer school, …：2运动和细胞-乔叟学院，…

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1、Whatisdiffusion?DiffusionandconcentrationWhycanthestudentsmellthesockfromadistance?Thesockcanbesmeltbecausesweatandothermoleculesaremovingawayfromitandspreadingoutintheair.Thisiscalleddiffusion.Whereisthesmellstrongest?Thesmellisstrongestatthesock.Thesmellbecomesweakerfurtherawayfromthesock.Movi

2、ngmoleculesInwhichstatesaremoleculesabletodiffuse?Moleculesinliquidsandgasesareconstantlymovingandbumpingintoeachother.Thismeansthattheytendtospreadout.gas(e.g.steam)liquid(e.g.water)solid(e.g.ice)Diffusioninaction:onegasDiffusioninaction:twogasesChangingconcentrationsTherateofdiffusiondependson

3、severalfactors,suchasthedistancetheparticleshavetotravelandthedifferenceinconcentration.Moleculesdiffuseuntiltheyareevenlyspacedapartandequilibriumisreached.Duringdiffusionmoleculesmovefromanareaofhighconcentrationtoanareaoflowconcentration.Theyaresaidtomovedownaconcentrationgradient.Diffusionis

4、apassiveprocesswhichmeansthatnoenergyisneeded.highconcentrationlowconcentrationDiffusion:trueorfalse?Whyisdiffusionimportanttolife?Diffusionisthemainwayinwhichsubstancesmoveovershortdistancesinorganisms.Whatsubstancesneedtomove?Oxygen,foodandwasteproductsaresomeofthesubstancesthatmovebydiffusion

5、.Inanimals,howdothesevitalsubstancesgettowheretheyareneeded?Thesubstancesaretransportedinthebloodstream,fromwheretheycandiffuseinandoutofcells.DiffusionandbreathingBreathinginvolvestheexchangeofgasesinthelungs;aprocessthatoccursbydiffusion.Whathappenswhenyoubreathein?Oxygenininhaledairdiffusesth

6、roughthelungsandintothebloodstream.Theoxygenisthentransportedthroughoutthebody.Carbondioxideisthewastegasproducedbyrespiration.Carbondioxidediffusesfrombodytissuesintothebloodstreamandisexhaledviathelungs.Wheredoesgasexchangetakeplaceinthelungs?StructuresoftherespiratorysystemCross-sectionthroug

7、hanalveolusdeoxygenatedblood(frombodytissues)oxygenatedblood(tobodytissues)airin/outAlveoliarethetinyairsacsattheendofthebronchioles,inwhichgasexchangeoccurs.alveoluscapillaryredbloodcellHowarealveoliadapted?Alveolihavesever