Yes, exocytosis does require energy. Exocytosis is a process by which cells transport molecules out of the cell by vesicles that fuse with the plasma membrane. This process is essential for various cellular functions, including the release of neurotransmitters, hormones, and other substances.
The energy required for exocytosis comes from ATP (adenosine triphosphate), which is the primary energy currency of the cell. During exocytosis, the vesicle containing the substances to be released moves toward the plasma membrane, and this movement often requires motor proteins that utilize ATP to facilitate the transport along the cytoskeletal elements like microtubules.
Additionally, the fusion of the vesicle with the plasma membrane and the subsequent release of its contents into the extracellular space is also an energy-dependent process. Therefore, exocytosis is categorized as an active transport mechanism, as it relies on energy to move substances against their concentration gradients and to perform the fusion of membranes.
In summary, without sufficient energy in the form of ATP, exocytosis cannot occur effectively, highlighting the crucial role of energy in maintaining cellular activities.