Which structure is characteristic of rough endoplasmic reticulum?

The characteristic structure of rough endoplasmic reticulum is cisternae. Cisternae are flattened membrane-bound sacs that are involved in the synthesis and processing of proteins. The rough endoplasmic reticulum is distinct from the smooth endoplasmic reticulum due to the presence of ribosomes on its cytoplasmic surface, giving it a "rough" appearance. These ribosomes are the sites of protein synthesis, which is a major function of the rough ER.

Cisternae facilitate the organization and localization of these ribosomes, allowing for efficient translation and folding of newly synthesized proteins. In contrast, mitochondria, the nucleus, and the Golgi body serve different functions in the cell. Mitochondria are responsible for energy production, the nucleus houses genetic material, and the Golgi apparatus is involved in modifying, sorting, and packaging proteins to be sent to their destinations. The specific association of cisternae with the rough endoplasmic reticulum underscores its key role in the protein synthesis pathway.