Question

Discuss briefly the role of nucleolus in the cells actively involved in protein synthesis.

Answer 1

Nucleolus

Nucleolus is a non membrane-bound spherical dense region present in the nucleoplasm.


Function of nucleolus

Nucleolus is the site of active rRNA transcription, processing and ribosome assembly. In the nucleolus, proteins imported from the cytoplasm get assembled with rRNA to form the precursors of large and small subunits of ribosomes. These subunits then exit the nucleus through the nuclear pores into the cytoplasm where the large and small subunits assemble to form a ribosome.

Protein synthesis

The basic steps in protein synthesis are as follows:-

* DNA is used as a template to synthesise

* mRNA in the nucleus. mRNA is transported to the cytoplasm.

* Ribosomes (subunits of which are formed in the nucleolus) translate the mRNA’s genetic message into proteins.

Therefore, cells actively carrying out protein synthesis have larger and more numerous nucleoli.