The largest organelle within a eukaryotic cell is the nucleus. The nucleus contains the cell’s DNA and controls the cell’s growth and reproduction. The nucleus is surrounded by a double membrane, called the nuclear envelope, which protects the DNA from damage. Inside the nucleus, there are two types of subatomic particles: protons and neutrons. Protons are positively charged, while neutrons have no charge. The number of protons in an atom determines its element. For example, all atoms with six protons are carbon atoms; all atoms with eight protons are oxygen atoms; all atoms with 79 protosn are gold atoms
