Which is NOT one of the three forms of membrane-facilitated uptake?

• A. Exocytosis
• B. Phagocytosis
• C. Pinocytosis
• D. Receptor Mediated endocytosis

Answer: (D)

Membrane-facilitated uptake brings materials into the cell by forming vesicles at the plasma membrane. The main forms are phagocytosis (cell eating), pinocytosis (cell drinking), and receptor-mediated endocytosis (specific uptake via receptors). Exocytosis, on the other hand, is the process of vesicles fusing with the membrane to release contents outside the cell, not to take things in. So the process not acting as a form of membrane-facilitated uptake is exocytosis.