the three ribosomal rna components , 18 s , 28 s and 5 s rna , appear in steep , specific radioactivity gradients ( exit gradients ) during the time interval 2-3 h after a precursor injection , the 18 s rna gradient lying 30-50 mum peripheral to that of the 28 s or 5 s rna gradient .
C0035701
ribosomal rna
C0035668
rna