Cell biology (also cellular biology or cytology) is a branch of
biology that studies the structure, function, and behavior of cells. All
organisms are made of cells. A cell is the basic unit of life that is
responsible for the living and functioning of an organism. Cell biology is the
study of the structural and functional units of cells. Cell biology
encompasses both prokaryotic and eukaryotic cells and has many subtopics which
may include the study of cell metabolism, cell communication, cell cycle,
biochemistry, and cell composition. The study of cells is performed using
several microscopy techniques, cell culture, and cell fractionation.