sentence: Potassium ions are very important to organisms.
sentences_after: They send messages from cells to other cells. It helps biological membranes 'depolarize'. This means go from a negative to a positive electrical charge. If the potassium level in the blood is too high or too low it can cause death because the heart stops. A few good sources of potassium are bananas, apricots and raisins.
concept_name: potassium ion
headings: Potassium Use by living organisms
categories: Alkali metals Chemical elements