Damn Near Everything There Is To Know About Cells: There are many parts of a cell, they all have specific duties, and are all needed to continue the life of the cell. Some cells exist as single-celled organisms that perform all of the organism's metabolism within a single cell. Such single-celled organisms are called unicellular. Other organisms are made up of many cells, with their cells specialized to perform distinct metabolic functions. One cell within an organism may be adapted for movement, while another cell carries out digestion. The individual cells no longer carry out all life functions, but rather depend on e