The human, and really, animal cell, has made a more than 3 billion year journey to be with us today in its present form. All life on this planet owes their humble beginnings to a shared single cell. Through all of these years, the single, then animal, then human cell has gone through many changes, adding other cells into its bigger self, evolving its DNA, until we have this cell you see before you. In investigating it, we are actually shining a light on our biological past, learning its history.
In the interactive guide to the human cell you find before you, each important structure in the cell has a plus sign next to it. Hover over the plus sign to open an explanation about that structure.