What type of cell structure is characterized by having ribosomes embedded in it?

The rough endoplasmic reticulum (RER) is characterized by having ribosomes embedded in its structure, which gives it a "rough" appearance under a microscope. These ribosomes are the sites of protein synthesis, allowing the RER to play a crucial role in the production and processing of proteins that are either secreted from the cell, incorporated into the cell's plasma membrane, or sent to an organelle.

The presence of ribosomes on the surface of the RER facilitates the translation of messenger RNA (mRNA) into polypeptide chains, which can then enter the lumen of the RER for further modifications, such as folding and addition of carbohydrate groups. This structural relationship highlights the specialized function of the rough endoplasmic reticulum in the overall cellular process of protein synthesis and processing, distinguishing it from other cell structures that do not have ribosomes associated with them.