A cell biologist compared the properties of rough endoplasmic reticulum (ER) and smooth ER. She found that one type of ER is used for protein storage, and the other is used for lipid storage. What accounts for this difference? a Rough ER forms proteins and transports them to the mitochondria. b Smooth ER works with the nucleus to synthesize protein. c Rough ER has ribosomes on its surface. d Smooth ER creates amino acids for ribosomes to form into proteins.

Answer 1

The correct answer is c. Rough ER has ribosomes on its surface.

The rough endoplasmic reticulum (Rough ER) is studded with ribosomes, which are the sites of protein synthesis. This is why it is primarily involved in the synthesis and initial processing of proteins, including those destined for export from the cell or for use in the cell membrane. In contrast, the smooth endoplasmic reticulum (Smooth ER) lacks ribosomes and is primarily involved in lipid synthesis, metabolism, and storage, as well as detoxification processes. Therefore, the presence of ribosomes on the Rough ER is what differentiates its function from that of the Smooth ER.