Ribosomal RNAs and subunit assembly

ribosomal RNAs (rRNAs)

are important components of the ribosome

ribosomal RNAs genes, what do they encode

• One gene encodes a precursor rRNA that is cut and modified to form three rRNAs

• Another gene encodes the other rRNA

RNA-protein complexes in the, what do they do

nucleolus process the precursor rRNA to form rRNAs

Base pairing between the precursor and small nucleolar RNAs (snoRNAs)

(snoRNAs)

small nucleolar RNAs

determines which bases are modified and where the precursor is cut

Ribosomal subunits assemble

in the nucleolus

rRNAs are synthesized and processed in

the nucleolus

Ribosomal proteins

bind to rRNAs to form the small subunit and large subunit (separately) in the nucleolus

• Small and large ribosomal subunits (separately) exit the nucleus

• Ribosomes assemble

on mRNAs and translate them in the cytosol and on the cytosolic side of the ER