Cells have to take in larger particles or polar molecules along with the smaller molecules. This requires another process called endocytosis. Endocytosis helps ingest the larger particles when the plasma membrane extends and surrounds the food particle. Then there are three different types of endocytosis; phagocytosis, pinocytosis, and receptor- meditated endocytosis. Each ending with vesicles with the certain molecules in them.
As shown above, the cell brings in food particles or bacterium particles through phagoctosis. The cell membrane brings liquids into the cell. Receptor-meditated endocytosis is more specific however. Specific molecules bind to specific receptors on the plasma membrane. When there are enough molecules in the pit, it deepens and closes off.