Science research . Space missions . Solar System . Volcanoes 101 . Site map .
Cells are the basic unit of life, and all living things are made of one or more cells.
Most cells have specialized roles, so it takes many kinds of cells to make up a complex being like you. A cell builds structures to support itself and moves them into place, and it acquires energy from the body to use in chemical and physical reactions needed to live and grow. The cell also sends proteins out into the body to control what the rest of the body does. A cell reproduces by dividing into two cells in a process called cell division. Twenty substances in the body that can be linked in any sequence to form proteins.