What anchors the cilium or flagellum in a cell?

The basal body serves as the anchor for cilia and flagella within a cell. It is a specialized structure located at the base of these organelles and is structurally similar to a centriole. The presence of microtubule triplets in the basal body organizes the assembly of the cilia or flagella, allowing for their function in movement or sensory roles.

In addition to anchoring, the basal body also plays a crucial role in the growth and maintenance of the cilia and flagella, providing a foundation for the microtubules that extend outward. The arrangement of these microtubules is integral to the movement of the cilia and flagella, allowing them to act effectively in locomotion or fluid movement across the surface of cells.

Other structures, like the centrosome, are involved in the organization of microtubules but do not specifically anchor cilia or flagella. Similarly, though microtubules are components of cilia and flagella, they themselves do not anchor these organelles within the cell. The cell membrane, while enclosing the entire cell and providing structure, is also not the anchor for cilia and flagella.