A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls.
1 The. 2  for a eukaryotic cell is the same kind of structure, and has the same function as the plasma membrane of a prokaryotic cell. ( 3 ER) is a system of membrane-enclosed channels which ramifies throughout the cytoplasm of the cell. 4  It comes in two types--smooth and rough. , which is quite different from the peptidoglycan of prokaryotic cell walls. 2  The primary function of the cell wall is support, and inconjunction with the central vacuole, to create turgor (stiffness) in plant structures like leaves. 3  Plant cells contain a specialized vacuole called the. .
Eukaryotic cells also have skin surrounding defined organelles with different functions inside them. Prokaryotes are cells that only have an outer membrane. The outermost membrane of cells serves as a selective barrier, allowing only certain molecules to enter and exit.