A flagellum (plural: flagella) is a long, slender 
projection from the cell body, composed of microtubules and 
surrounded by the plasma membrane. In small, single-cell 
organisms they may function to propel the cell by beating 
in a whip-like motion; in larger animals, they often serve 
to move fluids along mucous membranes such as the lining of 
the trachea.

A cell wall is a fairly rigid layer surrounding a cell, 
located external to the cell membrane, that provides the 
cell with structural support, protection, and a filtering 
mechanism.

flegella is a locomotive function of cell  with the help of 
flegella a cell move  whereas cell wall is a protactive 
function of cell  .