Receptor-mediated endocytosis is by

Very large paicles enter the cell by a specialized function of the cell membrane called endocytosis. The principal forms of endocytosis are pinocytosis and phagocytosis.Pinocytosis means ingestion of minute paicles that form vesicles of extracellular fluid and paiculate constituents inside the cell cytoplasm. Phagocytosis means ingestion of large paicles, such as bacteria, whole cells, or poions of degenerating tissue.Ref: Guyton; 13th edition; Chapter 2 The Cell and Its Functions