BOTH require energy from the cell Bulk Transport When molecules are too large to move through a channel protein or by using a carrier protein, vesicles are used to move the “bulk” molecule. Bulk transport of substances is accomplished by 1. endocytosis – movement of substances into the cell 2. exocytosis – movement of materials out of the cell BOTH require energy from the cell B3, B2.1, B3.6

Endocytosis occurs when the plasma membrane envelops food particles and liquids into a vesicle to take into the cell -3 types: B3, B2.1, B3.6

1. Phagocytosis (cell-eating)– the cell takes in particulate matter B3, B2.1, B3.6

2. Pinocytosis (cell-drinking) – the cell takes in only fluid B3, B2.1, B3.6

-the receptors are recycled for later use Receptor-mediated endocytosis – specific molecules are taken in after they bind to a receptor -the receptors are recycled for later use B3, B2.1, B3.6

Exocytosis occurs when material is discharged from the cell. -vesicles in the cytoplasm fuse with the cell membrane and release their contents to the exterior of the cell -used in animals to secrete hormones, neurotransmitters, digestive enzymes, etc B3, B2.1, B3.6