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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
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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
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