In what important way does receptor-mediated endocytosis differ from phagocytosis?

• A. Phagocytosis requires the presence of clathrin-coated pits for vesicle formation.
• B. Receptor-mediated endocytosis involves the selective uptake of molecules based on receptor-ligand interactions.
• C. Receptor-mediated endocytosis is a non-selective process that engulfs large particles.
• D. Phagocytosis is primarily used for the uptake of small molecules and ions.

Answer: (B)

Verified step by step guidance

1. Understand the basic definitions: Phagocytosis is a process where cells engulf large particles or even other cells, often used by immune cells to ingest harmful pathogens. Receptor-mediated endocytosis is a more selective process where cells internalize specific molecules bound to receptors on the cell surface.
2. Identify the key difference: Receptor-mediated endocytosis involves specific receptor-ligand interactions, meaning it is selective for certain molecules. This is in contrast to phagocytosis, which is generally non-selective and used for larger particles.
3. Consider the role of clathrin: In receptor-mediated endocytosis, clathrin-coated pits are involved in the formation of vesicles that internalize the receptor-ligand complexes. This is a crucial part of the selectivity of the process.
4. Clarify the misconception: Phagocytosis does not typically involve clathrin-coated pits and is not primarily used for the uptake of small molecules and ions. Instead, it is used for larger particles.
5. Summarize the main point: The main difference is that receptor-mediated endocytosis is a selective process based on receptor-ligand interactions, while phagocytosis is a non-selective process used for engulfing larger particles.