Cells are important for living organisms because cells are the basic building blocks from which all organisms are created. While some organisms are comprised of a single cell, others are multicellular entities with different cell types.
Humans, for example, have many different types of cells, including nerve cells, skin cells and fat cells. Each type of cell is important for a different purpose. For example, according to the University of Rochester Medical Center, fat cells are important because they serve as an energy source, provide protection to internal organs and play a role in the regulation of women's menstrual cycles.