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 Smooth ER works with the nucleus to synthesize protein. c Rough ER has ribosomes on its surface. d Rough ER forms proteins and transports them to the mitochondria.

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. The presence of these ribosomes allows the Rough ER to synthesize and process proteins that are either destined for secretion, integration into cellular membranes, or for use in lysosomes.

In contrast, the smooth endoplasmic reticulum (Smooth ER) lacks ribosomes and is primarily involved in the synthesis of lipids, as well as the metabolism of carbohydrates and the detoxification of drugs and poisons. Therefore, the properties associated with each type of ER are a direct result of the presence of ribosomes on the Rough ER.