Ribosomes have following enzymatic activity -

Ans. is 'a' i.e., Peptidyi transferaseo Ribosomes are large complexes of r-RN A and proteins with one large and one small subunits.o The small subunit binds m-RNA, thus guiding interaction between m-RNA codon and anticodon of t-RNA to read the genetic information with exiquisite fidelity.o Hence small subunit is responsible for accuracy, whereas the large subunit catalyzes the formation of peptide bond.o Ribosomes are composed of two unequal subunitsQ.Eukaryotic (80 S) ribosome is made up of 60 S and 40 S subunits, andProkaryotic (70S) ribosome is made of 50S and 30S subunits. 60S subunit of eukaryotes contains 5 S rRNA, 5.8 S rRNA, 28S rRNA and more than 50 polypeptides. 40 S subunit contains 18 S rRNA and about 30 polypeptide chains.o The formation of peptide bonds is catalysed by peptidyi transferase, an activity intrinsic to the 23S r-RNA of 50 S subunit in prokaryotes and 28 S r-RNA of 60 S subunit in eukaryotes. So, it is referred as ribozyme & indicates direct role of r-RNA in protein synthesis.