Atoms that have a neutral charge have an equal number of protons and electrons. Protons are positively charged and electrons are negatively charged, so to cancel out all charges, the number of both these particles must be equal. If there is an unequal amount, then it is called an ion. Ions are atoms that have either a negative or positive charge because the amount of protons and electrons is not balanced.
Mitochondria are membrane-bound cell organelles that generate most of the energy required to power the cell's organic chemistry reactions. Energy created by the mitochondria is kept in a tiny molecule known as adenosine triphosphate (ATP).
