Which structure found inside the nucleus synthesizes ribosomes?

Which structure found inside the nucleus synthesizes ribosomes?

• A. Nucleolus
• B. Endoplasmic reticulum
• C. Mitochondrion
• D. Golgi apparatus

Answer: (A)

Ribosome synthesis happens in the nucleolus, a dense region inside the nucleus where ribosomal RNA genes are transcribed and ribosomal subunits are assembled. Here, rRNA is produced and combines with ribosomal proteins imported from the cytoplasm to form the large and small subunits, which are then exported to the cytoplasm to become functional ribosomes. The endoplasmic reticulum translates proteins but does not assemble ribosomal subunits inside the nucleus. The mitochondrion has its own ribosomes for mitochondrial protein synthesis, not for making cytoplasmic ribosomal subunits. The Golgi apparatus handles modification and shipping of proteins, not ribosome assembly.

Ribosome synthesis happens in the nucleolus, a dense region inside the nucleus where ribosomal RNA genes are transcribed and ribosomal subunits are assembled. Here, rRNA is produced and combines with ribosomal proteins imported from the cytoplasm to form the large and small subunits, which are then exported to the cytoplasm to become functional ribosomes. The endoplasmic reticulum translates proteins but does not assemble ribosomal subunits inside the nucleus. The mitochondrion has its own ribosomes for mitochondrial protein synthesis, not for making cytoplasmic ribosomal subunits. The Golgi apparatus handles modification and shipping of proteins, not ribosome assembly.