Endocytosis

Definition

Endocytosis is a cellular process where the cell membrane engulfs external substances, forming vesicles to internalize them. This mechanism is essential for nutrient uptake, receptor signaling, and pathogen defense.

5 Must Know Facts For Your Next Test

1. Endocytosis can be categorized into phagocytosis, pinocytosis, and receptor-mediated endocytosis.
2. Phagocytosis involves the ingestion of large particles or cells, often used by immune cells to engulf pathogens.
3. Pinocytosis is the process of taking in extracellular fluid and dissolved solutes through small vesicles.
4. Receptor-mediated endocytosis uses specific receptors on the cell surface to selectively internalize molecules like hormones and nutrients.
5. Clathrin-coated pits are specialized regions of the plasma membrane involved in receptor-mediated endocytosis.

Review Questions

• What are the three main types of endocytosis?
• How does receptor-mediated endocytosis differ from pinocytosis?
• What role do clathrin-coated pits play in endocytosis?

Related terms

Phagocytosis:

The process where cells engulf large particles or other cells, often used by immune cells.

Pinocytosis: A form of endocytosis where cells ingest extracellular fluid and its dissolved solutes through small vesicles.

Exocytosis:

The process by which cells expel materials using vesicles that fuse with the plasma membrane.