Question

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 Smooth ER creates amino acids for ribosomes to form into proteins. b Rough ER forms proteins and transports them to the mitochondria. c Rough ER has ribosomes on its surface. d Smooth ER works with the nucleus to synthesize protein.

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 involved in the production and processing of proteins. In contrast, the smooth endoplasmic reticulum (smooth ER) lacks ribosomes and is involved in lipid synthesis and storage, as well as other functions like detoxification and calcium storage. Thus, the presence of ribosomes on the rough ER is what primarily differentiates it from the smooth ER in terms of their functions related to protein and lipid storage.