All cells host a variety of chemical reactions that enable them to grow, produce energy, and eliminate waste. Together these reactions are termed metabolism (from a Greek word meaning, "change"). All cells contain hereditary information, encoded in molecules of deoxyribonucleic acid (DNA), that directs the cell's activities and enables it to reproduce, passing on its characteristics to its offspring. These and other numerous similarities (including many identical or nearly identical molecules) demonstrate that there is an unbroken link between modern cells and the first primitive cells that appeared on earth.
In the cells of a beetroot plant, a substance called anthocyanin is contained within the plasma membrane. It is anthocyanin, which gives the beetroot its characteristic bluepurple colour. If a cell is damaged in a beetroot plant and the membrane is broken, the anthocyanin 'bleeds' from the cells like a dye. It is this characteristic that can be exploited to test which conditions affect the integrity of the cell membran