Which of the following correctly states the functions of the rough endoplasmic reticulum?

• A. Detoxification of drugs and poisons
• B. Synthesis of proteins destined for secretion or membrane insertion
• C. Synthesis of lipids and steroids
• D. Storage of calcium ions

Answer: (B)

Verified step by step guidance

1. Understand the structure of the rough endoplasmic reticulum (RER): It is characterized by the presence of ribosomes on its surface, which gives it a 'rough' appearance under a microscope.
2. Recognize the primary function of ribosomes: Ribosomes are the cellular machinery responsible for protein synthesis.
3. Connect the presence of ribosomes on the RER to its function: The ribosomes on the RER synthesize proteins, particularly those that are destined for secretion outside the cell or for insertion into cellular membranes.
4. Differentiate the functions of the rough and smooth endoplasmic reticulum: The smooth endoplasmic reticulum (SER) is involved in lipid and steroid synthesis, detoxification of drugs and poisons, and storage of calcium ions, which are not functions of the RER.
5. Conclude that the correct function of the rough endoplasmic reticulum is the synthesis of proteins destined for secretion or membrane insertion, as it is directly related to the presence of ribosomes on its surface.