What is the primary difference between the rough endoplasmic reticulum (ER) and the smooth endoplasmic reticulum (ER) in eukaryotic cells?

• A. The rough ER is involved in lipid synthesis, while the smooth ER is involved in protein synthesis.
• B. The rough ER is found only in animal cells, while the smooth ER is found only in plant cells.
• C. The rough ER has ribosomes on its surface, while the smooth ER does not.
• D. The rough ER is responsible for detoxification, while the smooth ER is responsible for calcium storage.

Answer: (C)

Verified step by step guidance

1. Begin by understanding the structure and function of the endoplasmic reticulum (ER) in eukaryotic cells. The ER is a network of membranes within the cell that plays a crucial role in the synthesis and transport of proteins and lipids.
2. Differentiate between the rough ER and the smooth ER based on their physical characteristics. The rough ER is studded with ribosomes on its cytoplasmic surface, giving it a 'rough' appearance under a microscope.
3. Recognize the primary function of the rough ER. The presence of ribosomes allows the rough ER to be involved in the synthesis of proteins, particularly those that are secreted by the cell or inserted into the cell membrane.
4. Understand the function of the smooth ER. Unlike the rough ER, the smooth ER lacks ribosomes and is primarily involved in lipid synthesis, metabolism, and detoxification processes.
5. Conclude by identifying the key difference: The rough ER has ribosomes on its surface, which are essential for protein synthesis, while the smooth ER does not have ribosomes and is involved in lipid synthesis and other functions.