Exocytosis

Active transport and bulk transport in which a cell transports molecules out of the cell

Exocytosis is a form of active transport in which a cell transports molecules (e.g., neurotransmitters and proteins) out of the cell. As an active transport mechanism, exocytosis requires the use of energy to transport material. Exocytosis and its counterpart, endocytosis, are used by all cells because most chemical substances important to them are large polar molecules that cannot pass through the hydrophobic portion of the cell membrane by passive means.

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