The document discusses the nucleolus, which was discovered in the 19th century. It is located in the nucleus of eukaryotic cells and can vary in size. The nucleolus has an intricate internal structure and plays an important role in ribosomal biogenesis through its involvement in the synthesis and assembly of ribosomal RNA and ribosomal subunits.

1. NUCLEOLUS

2. CONTENTS
INTRODUCTION
DISCOVERY
POSITION
SIZE
ULTRASTRUCTURE
FUNCTIONS
RIBOSOMAL BIOGENESIS

3. INTRODUCTION

6. DISCOVERY

7. POSITION

8. SIZE

9. ULTRASTRUCTURE

12. FUNCTIONS

13. RIBOSOMAL BIOGENESIS