Vesicle Formation by Cellular Structures

Steps:

• Vesicles are small membrane-bound sacs that transport materials within cells.
• Identify key sites: plasma membrane buds inward to form endocytic vesicles.
• Endoplasmic reticulum (ER) synthesizes proteins and lipids but primarily sends them via transport vesicles from its membrane to Golgi.
• Golgi body modifies and packages molecules into secretory vesicles for export.

Why A is correct:

• Cell surface membrane forms vesicles via endocytosis (invagination and budding), and Golgi body forms vesicles by budding off transport and secretory sacs, per the endomembrane system's vesicle trafficking definition.

Why the others are wrong:

• B: Incorrect symbols (/ for membrane and ER) misrepresent vesicle formation sites.
• C: Fails to mark cell surface membrane as a vesicle former, ignoring endocytosis.
• D: Wrongly excludes cell surface membrane, overlooking its role in vesicle production.

Final answer: A