It is the basic unit of life. A cell is the smallest basic unit of life responsible for all of lifes processes. The Fundamental Unit Of Life Is The Cell Without At Least 1 Cell An Animal Cell Plant And Animal Cells Cell Diagram In unicellular organism single cell is. . Why is the cell called the structural and functional unit of life. Because all living organisms are made up of cells the cell is the basic construction unit of a living organism and all of a living organisms activities are the sum of activities conducted by its cells the cell is referred to as the structural and functional unit of. Share to Twitter Share to Facebook Share to Pinterest. NIAGEN nicotinamide riboside increases cellular levels of NAD. 6 In 1855 Rudolf Virchow added the third tenet to cell theory. The cell is the most basic unit of life Schleidens theory of free cell formation through crystallization was refuted in the 1850s by Robert Remak Rudol