How are the rough endoplasmic reticulum (ER) and smooth endoplasmic reticulum (ER) different?

• A. The rough ER contains ribosomes on its surface, while the smooth ER does not.
• B. The rough ER is involved in detoxification processes, while the smooth ER is not.
• C. The rough ER is responsible for lipid synthesis, while the smooth ER is responsible for protein synthesis.
• D. The rough ER is involved in protein synthesis, while the smooth ER is involved in lipid synthesis.

Answer: (D)

Verified step by step guidance

1. Understand the structure of the endoplasmic reticulum (ER): The ER is a network of membranes within the cell, and it comes in two forms - rough and smooth.
2. Identify the rough ER: The rough ER is characterized by the presence of ribosomes on its surface, which gives it a 'rough' appearance under a microscope.
3. Identify the smooth ER: The smooth ER lacks ribosomes on its surface, giving it a 'smooth' appearance.
4. Differentiate their functions: The rough ER is primarily involved in protein synthesis due to the presence of ribosomes, which are the sites of protein assembly.
5. Differentiate their functions further: The smooth ER is involved in lipid synthesis and detoxification processes, as it does not have ribosomes and thus does not directly participate in protein synthesis.