Final answer:
Vesicles in animal cells are transported over long distances by motor proteins along microtubules, utilizing ATP to move in either an anterograde direction, facilitated by kinesin, or retrograde, by dynein.
Step-by-step explanation:
The unconventional movement of vesicles over long distances in animal cells occurs on microtubules.
Within the eukaryotic cells, organelles and vesicles utilize motor proteins such as dynein and kinesin to facilitate intracellular transport. These proteins are ATPases, meaning that they harness the energy from ATP hydrolysis to generate mechanical work required for movement. For example, vesicles containing neurotransmitters are transported from the neuron cell body to the nerve endings by kinesin. This is known as anterograde transport. Conversely, dynein, working with the dynein-dynactin complex, drives the retrograde transport of vesicles, moving them in the opposite direction, from the nerve endings back to the neuron cell body. The microtubules are critical for the movement of vesicles, providing a structural track upon which the motor proteins traverse, towing their cargo to the intended destinations within cells.
Vesicle transport is essential for various cellular processes such as exocytosis, where secretory vesicles merge with the plasma membrane to release their contents outside the cell. Moreover, these movements are not limited to just transport within the cell; they also contribute to larger scale movements like those seen in cilia and flagella, which result from the motor protein dynein facilitating the bending of microtubules in the axonemes.