Which of the following statements about the endoplasmic reticulum (ER) is false?

• A. The ER is directly involved in the packaging of proteins into vesicles for secretion.
• B. The rough ER is involved in protein synthesis.
• C. The smooth ER is responsible for lipid synthesis.
• D. The ER is responsible for the synthesis of nucleic acids.

Answer: (D)

Verified step by step guidance

1. Understand the role of the endoplasmic reticulum (ER) in the cell. The ER is a network of membranes involved in various cellular processes, including protein and lipid synthesis.
2. Differentiate between the rough ER and smooth ER. The rough ER is studded with ribosomes and primarily involved in protein synthesis, while the smooth ER lacks ribosomes and is involved in lipid synthesis and detoxification processes.
3. Evaluate the statement about the ER being directly involved in the packaging of proteins into vesicles for secretion. The ER works closely with the Golgi apparatus to package proteins, but the primary packaging occurs in the Golgi apparatus.
4. Consider the statement about the ER being responsible for the synthesis of nucleic acids. Nucleic acids, such as DNA and RNA, are synthesized in the nucleus, not the ER.
5. Identify the false statement by comparing each statement with the known functions of the ER. The false statement is the one claiming the ER is responsible for the synthesis of nucleic acids, as this is not a function of the ER.