endocytosis

What is endocytosis?

Endocytosis is a cellular process by which substances are brought into the cell. The material to be internalized is engulfed by an area of the cell membrane, which then buds off inside the cell to form a vesicle containing the ingested material. It is a form of active transport.

What are the three main types of endocytosis?

The three main types of endocytosis are:

1. Phagocytosis
2. Pinocytosis
3. Receptor-mediated endocytosis

Phagocytosis

Phagocytosis, also known as "cell eating," is a process where the cell engulfs large particles, such as bacteria, other cells, or cellular debris, to form a phagosome. This process is common in immune cells like macrophages and neutrophils.

Pinocytosis

Pinocytosis, or "cell drinking," is a process where the cell takes in fluids and dissolved small molecules by forming small vesicles. Unlike phagocytosis, it is non-specific regarding the substances it ingests.

Receptor-mediated endocytosis

Receptor-mediated endocytosis is a highly specific process where specific molecules (ligands) bind to receptors on the cell surface. These receptor-ligand complexes then accumulate in coated pits (often clathrin-coated pits) which invaginate to form coated vesicles, internalizing the specific substances.