ru-第6章 细胞质核糖体 20161025(1).pptVIP免费

1CHAPTER6Cytoplasm,RibosomeandRNAs2OUTLINE6.1Structureandfunctionofcytoplasm6.2Ribosome6.3RibozymeandNon-codingRNAs•Cytosol:–dissolvednutrientsandwasteproducts–dissolvedmacromolecules,suchasRNAsandproteins–manysalts•Organelles•Cytoskeleton•Cytoplasmicinclusions6.1.1StructureofcytoplasmOrganelles(1)nucleolus;(2)nucleus;(3)ribosomes;(4)vesicle;(5)roughendoplasmicreticulum(ER);(6)Golgiapparatus;(7)cytoskeleton;(8)smoothER;(9)mitochondria;(10)vacuole;(11)cytosol;(12)lysosome;(13)centrioleswithincentrosomeCytoplasmicinclusions•crystalsofcalciumoxalateorsilicondioxideinplants(草酸钙或二氧化硅)•granulesofstarch,glycogen,orpolyhydroxybutyrate(聚羟基丁酸酯),whichcanstoreenergy.•Lipiddroplets,storingfattyacidsandsterols•Metabolicpathwaysandbiochemicalreactions•Ubiquitin-proteasomesystem•Functionsoforganelles•Maintenanceandmovement•Storage6.1.2Functionsofcytoplasm76.2Ribosome8◆核糖体(ribosome)Theribosomeisaribonucleoproteinparticle(核糖核蛋白颗粒)composedofRNAandprotein，andservesasthesiteofproteinsynthesis.◆核糖体的主要成分ribosomeRNA(rRNA)：60%ribosomeprotein：40%6.2.1Ribosomestructure9Ribosomesubunits10TypesofRibosomesTypeProkaryotesEukaryotessediments70S80SMolecularweight2.5x103kD3.9~4.5x103kDsubunits50Sand30S60Sand40SAbundance15×102-18×103/cell106-107/cellotherpolyribosomeorpolysomefreeribosomemembrane-boundpolyribosomeorpolysome11ChemicalCompositionofRibosome12CompositionsofribosomefromdifferentsourcesSourceRibosomeSubunitsribosomalRNAsCytoplasm80S60S(大亚基)28S(Eukaryote)40S(小亚基)18S,5.8S,5SCytoplasm70S50S(大亚基)23S(Prokaryote)30S(小亚基)16S,5SMitochondrion55-60S45S(大亚基)16S(Mamalian)35S(小亚基)12SMitochondrion75S53S(大亚基)21S(Yeast)35S(小亚基)14SMitochondrion78S60S(大亚基)26S(Plant)45S(小亚基)18S,5SChloroplast70S50S(大亚基)23S30S(小亚基)16S,5S13Mg2+andsubunitassemblyinribosome◆70S核糖体在Mg2+的浓度小于1mM的溶液中易解离;◆当Mg2+浓度大于10mM,两个核糖体通常形成100S的二聚体。146.2.2BiogenesisofRibosome◆selfassemblyincellswithdifferentpro...