What is a stem cell? A cell that is capable of proliferation, self-renewal and differentiation into at least one cell type. These are the minimum properties of a stem cell.
Self renewing: They are able to give rise to another cell type and this other cell type will expand the population but not require expansion itself. Eventually this cell type will need by definition to differentiate into a specific cell type. Determination: when start going down a specific lineage, cells that come off cell lineage begin to differentiate. All of them could be identical of different into capacities to differentiate into different cell types.
A stem cell can divide by 2 forms of division and the consequence of dividing by one of these modes of division will cause the stem cell to be different.
