MICROANATOMY

Detailed explanation-1: -The rough endoplasmic reticulum (RER) is so named for the appearance of its outer surface, which is studded with protein-synthesizing particles known as ribosomes.

Detailed explanation-2: -Ribophorin, also known as a ribosome receptor protein, is a transmembrane glycoprotein that aids in the binding of ribosomes to the endoplasmic reticulum’s outer surface, generating rough endoplasmic reticulum. They attach the ribosome’s larger subunit (the 50S) to the rough endoplasmic reticulum.

Detailed explanation-3: -Answer and Explanation: The portion of the ER studded with ribosome is the outer surface of the rough endoplasmic reticulum. Therefore, they are also called the granular endoplasmic reticulum.

Detailed explanation-4: -The ribosome that is synthesizing the protein is directly attached to the ER membrane. These membrane-bound ribosomes coat the surface of the ER, creating regions termed rough endoplasmic reticulum, or rough ER (Figure 12-36A).