原核生 真核生 物核糖 物核糖 体组成 体组成 MW2,500,000 MW4,200000 30s 60s 40s MW1.600,000 MW900,000 Mw2,800,000 MW1,400,000 ES TRNA 23S rRNA 16S rRNA 5S rRNA 28S rRNA 5.8S rRNA 18S rRNA a nucleotides 1900 2900 1540 nucleotides nucleotides nucleotides nucleotides nucleotides 470 34 proteins 21 proteins -49 proteins -33 proteins EUCARYOTIC RIBOSOME PROCARYOTIC RIBOSO原核生 物核糖 体组成 真核生 物核糖 体组成