Question

the difference between pinocytosis and receptor - mediated endocytosis is that...

pinocytosis brings only water molecules into the cell, whereas receptor - mediated endocytosis brings in other molecules as well.

pinocytosis increases the surface area of the plasma membrane, whereas receptor mediated endocytosis decreases the plasma membrane surface area.

pinocytosis is nonselective in the molecules it brings into the cell, where as receptor - mediated endocytosis is highly selective.

pinocytosis requires cellular energy, but receptor - mediated endocytosis does not.

pinocytosis generally concentrates substances from the extracellular fluid, but receptor - mediated endocytosis does not.

Explanation:

• Pinocytosis is a non - selective process where the cell takes in extracellular fluid along with all the dissolved molecules in it.
• Receptor - mediated endocytosis is highly selective. It involves specific receptors on the cell membrane that bind to specific ligands (molecules). Only when the ligand binds to the receptor, the process of endocytosis occurs for that particular molecule.
• Pinocytosis does not just bring water (so the first option is wrong). Both pinocytosis and receptor - mediated endocytosis decrease the plasma membrane surface area (as a vesicle is formed from the plasma membrane, so the second option is wrong). Both pinocytosis and receptor - mediated endocytosis are active processes and require cellular energy (so the fourth option is wrong). Receptor - mediated endocytosis can concentrate substances (for example, the uptake of low - density lipoproteins (LDL) is a receptor - mediated endocytosis process that concentrates LDL in the cell, so the fifth option is wrong).

Answer:

pinocytosis is nonselective in the molecules it brings into the cell, where as receptor - mediated endocytosis is highly selective.