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.
Organelles are parts of the cell which are adapted and/or specialized for carrying out one or more vital functions, analogous to the organs of the human body (such as the heart, lung, and kidney, with each organ performing a different function).ost important among these is a cell nucleus, an organelle that houses the cell's DNA. This nucleus gives the eukaryote its name, which means true kernel (nucleus). Other differences include: 1  The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup.
The following short list of key features of eukaryotic cells can be used to describe eukaryotic cells without much reference to prokaryotic cells. 1  Contain membranous and non-membranous organelles that have specific functions within the cell. For example, all eukaryotic cells have (or had*1) a nucleus. Different eukaryotic cells contain different types and quantities of other organelles depending on the type and function of the particular cell e.g. many plant cells contain chloroplasts which are the sites of photosynthesis within those cells.