The cell structure that performs a function similar to the bark of a tree is the cell wall.

Here's why:

* Bark's function: Bark provides a protective outer layer for the tree, shielding it from damage, infection, and water loss.

* Cell wall's function: The cell wall is a rigid, outer layer that surrounds plant cells. It provides structural support, protects the cell, and regulates the movement of substances in and out of the cell.

While bark is a much more complex structure, the cell wall shares its basic function of providing protection and support.