The membranes of the endoplasmic reticulum form which of the following structures involved in protein secretion?

• A. Vesicles
• B. Peroxisomes
• C. Cisternae
• D. Lysosomes

Answer: (C)

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 protein and lipid synthesis.
2. Differentiate between the two types of ER: Rough ER, which is studded with ribosomes and involved in protein synthesis, and Smooth ER, which is involved in lipid synthesis and detoxification processes.
3. Recognize that the membranes of the ER form structures called cisternae, which are flattened, membrane-bound sacs that play a crucial role in the synthesis and transport of proteins.
4. Identify that vesicles are small membrane-bound sacs that transport substances within the cell, but they are not formed by the ER membranes themselves.
5. Clarify that peroxisomes and lysosomes are organelles involved in different cellular processes, such as breaking down fatty acids and digesting cellular waste, respectively, and are not directly formed by the ER membranes.