资源描述:
《chapter 05 biomembranes and cell architecturenew》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、5BIOMEMBRANESANDCELLARCHITECTUREAtomicforcemicroscopyrevealssphyingomyelinrafts(orange)protrudingfromadioleoylphosphatidylcholinebackground(black)inamica-supportedlipidbilayer.Placentalalkalinephosphatase(yellowpeaks),aglycosylphosphatidylinositol-anchoredprote
2、in,isshowntobealmostexclusivelyraftassociated.[FromD.E.Saslowskyetal.,2002,J.Biol.Chem.277:26966–26970.]rokaryotes,whichrepresentthesimplestandsmallestAlthoughthebasicarchitectureofalleukaryoticcellsiscells,about1–2minlength,aresurroundedbyaconstructedfrommemb
3、ranes,organelles,andthecytosol,Pplasmamembranebutcontainnointernalmembrane-eachtypeofcellexhibitsadistinctivedesigndefinedbythelimitedsubcompartments(seeFigure1-2a).AlthoughDNAisshapeofthecellandthelocationofitsorganelles.Thestruc-concentratedinthecenterofthese
4、unicellularorganisms,mostturalbasisoftheuniquedesignofeachcelltypeliesintheenzymesandmetabolitesarethoughttodiffusefreelywithincytoskeleton,adensenetworkofthreeclassesofproteinfila-thesingleinternalaqueouscompartment.Certainmetabolicmentsthatpermeatethecytosola
5、ndmechanicallysupportcel-reactions,includingproteinsynthesisandanaerobicglycolysis,lularmembranes.Cytoskeletalproteinsareamongthemosttakeplacethere;others,suchasthereplicationofDNAandabundantproteinsinacell,andtheenormoussurfaceareaoftheproductionofATP,takeplac
6、eattheplasmamembrane.thecytoskeleton(seeFigure5-1)constitutesascaffoldtoInthelargercellsofeukaryotes,however,theratesofwhichparticularsetsofproteinsandmembranesarebound.chemicalreactionswouldbelimitedbythediffusionofsmallWebeginourexaminationofcellarchitectureb
7、yconsid-moleculesifacellwerenotpartitionedintosmallersubcom-eringthebasicstructureofbiomembranes.Thelipidcom-partmentstermedorganelles.Eachorganelleissurroundedponentsofmembranesnotonlyaffecttheirshapeandbyoneormorebiomembranes,andeachtypeoforganellecontainsaun
8、iquecomplementofproteins—someembeddedinitsmembrane(s),othersinitsaqueousinteriorspace,orOUTLINElumen.Theseproteinsenableeachorganelletocarryoutitscharacteristiccellularfunct