Question

Which of the following is present within the nucleolus?

• A. rRNA, proteins but no DNA
• B. rRNA, DNA but no proteins
• C. rRNA, proteins and small amount of DNA
• D. Only rRNA and DNA

Answer 1

Answer: (B)

rRNA, DNA but no proteins

The nucleolus is naked, roughly rounded, darkly stained structure. It is attached to chromosome at a specific spot called Nucleolar Organiser Region or NOR. Nucleolus contains four parts- Amorphous, Fibrillar, Granular and Chromatin. Both fibrillar and granular parts are formed of RNA and proteins. The nucleolus is the site for the elaboration of rRNA and synthesis of ribosomes. It is, therefore, called Ribosomal Factory. Ribosomal protein is synthesised in the cytoplasm.

So, the correct answer is 'rRNA, DNA but no proteins'