Cell Culture  

Isolated cells can be grown in a plastic culture dish under  suitable  condi- tions with defined growth medium. Directly Cultures prepared from the tissues of an organism are referred to as primary cultures, whereas cells that have been made to proliferate to form large numbers and which may be repeatedly subcultured for weeks or months are referred to as secondary cultures. Various cells in culture received the differentiated properties suitable to their origin.  For an example, fibroblasts continue to secrete collagen, and nerve cells extend axons. Cultured cells give a large number of identical cells that can be used for a variety of cell biological and biochemical studies.