In prokaryotes, rRNA is synthesized and attached to proteins in a region called the _____.

• A. Nucleoid
• B. Nucleolus
• C. Cytoplasm
• D. Ribosome

Answer: (B)

In prokaryotes, there is no nucleus or nucleolus. The nucleolus is a eukaryotic structure where rRNA genes are transcribed and ribosomal subunits begin to assemble with ribosomal proteins. In bacteria and archaea, rRNA transcription occurs directly in the cytoplasm, and ribosomal proteins are synthesized there as well, with the rRNA folding and assembling into ribosomal subunits in the cytoplasm. Transcription and translation are typically coupled in prokaryotes, and there isn’t a separate compartment dedicated to ribosome assembly. So, for prokaryotes, the region where rRNA is synthesized and combines with proteins is the cytoplasm. The nucleoid houses the chromosome, and the ribosome is the complex that forms, not a region.