A cell is the smallest living organism and the basic unit of life on earth. Together, trillions of cells make up the human body. Cells have three main parts: the membrane, the nucleus, and the ... cell, in biology, the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed. A single cell is often a complete organism in itself, such as a bacterium or yeast. Other cells acquire specialized functions as they mature. Introduction to the cell | Cells | High school biology | Khan Academy Fundraiser Khan Academy 9.11M subscribers Cells vary in size and structure as they are specialized to perform different functions. But the basic components of the cell are common to all biological cells . This lesson deals with the structure common to all types of the cells . You will also learn about the kinds of cell division and the processes involved therein in this lesson.
