Ribosomal RNA is synthesised in

Options

A. lysosomes
B. nucleolus
C. nucleoplasm
D. ribosomes

Answer

B

Explanation

In eukaryotes, the site of synthesis of most ofthe ribosomal RNA (rRNA) is nucleolus. Thenucleolar organiser contains many copies of ribosomal DNA (repetitive DNA). The RNA cistron
of nucleolar DNA forms 45S precursor with the help of RNA polymerase. This 45S RNA undergoes cleavage with the help of nucleases to give 18S, 28S and 5.8S rRNA units. Out of different rRNAs, the 5S rRNA is not synthesised in nucleolus. It is synthesised outside it