Endocytosis & Exocytosis
1. Endocytosis
Cell takes contents in (i.e.., from ECF to cytoplasm).
Steps:
On contact with large molecule, cell membrane invaginates forming vesicle, including macromolecule.
Vesicle is pinched within cell & restoring cell membrane.
Requires energy, Ca++ & contractile elements in cell.
2. Exocytosis/endocytosis/reverse pinocytosis:
Reverse of endocytosis.
Process of extrusion of secretory granules from cell.
On contact of secretory vesicle with cell membrane, vesicular fusing & subsequent vesicular content extrusion takes place à Extruded as secretory granules.
Requires energy, Ca+.
