Which of the following is a function of the rough endoplasmic reticulum (ER)?

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

Answer: (C)

Verified step by step guidance

1. Understand the structure of the rough endoplasmic reticulum (ER): It is characterized by the presence of ribosomes on its surface, which gives it a 'rough' appearance under a microscope.
2. Recognize the role of ribosomes: Ribosomes are the cellular structures responsible for protein synthesis. Their presence on the rough ER indicates its involvement in protein production.
3. Identify the primary function of the rough ER: The rough ER is primarily involved in the synthesis of proteins, particularly those that are destined for secretion outside the cell or for use in the cell membrane.
4. Differentiate between rough and smooth ER: The smooth ER, which lacks ribosomes, is involved in lipid synthesis, detoxification of drugs and poisons, and storage of calcium ions, distinguishing its functions from those of the rough ER.
5. Conclude that the synthesis of proteins destined for secretion is the main function of the rough ER, aligning with the presence of ribosomes and its structural characteristics.