Which structure is primarily involved in the movement of cell organelles along microtubules?

The structure primarily involved in the movement of cell organelles along microtubules is dynein. Dynein is a motor protein that moves along the microtubules towards the minus end, which is typically oriented towards the cell center. This movement is crucial for various cellular processes, including the transport of organelles, vesicles, and even chromosomes during cell division.

While kinesin also functions as a motor protein that transports organelles along microtubules, it moves towards the plus end, which is generally directed away from the cell center. The distinction between dynein and kinesin is important because they have opposite directionalities and, together, they facilitate cargo transport in both directions along the microtubule tracks.

Cilia and flagella are structures composed of microtubules that are involved in cell motility but are not responsible for the movement of organelles along microtubules within the cell. Instead, they play roles in propelling cells and moving fluid across surfaces.

Understanding the roles of dynein and kinesin allows for a clearer grasp of intracellular transport mechanisms and the specific functions that different proteins play in cellular dynamics.