Stem cell. Coloured transmission electron micrograph (TEM) of a section through a stem cell. The majority of the cell is taken up by the nucleus (red and yellow), which holds the cell's genetic information in the form of DNA (deoxyribonucleic acid). Within the nucleus is the nucleolus (pink), the site of ribosome production. Within the cell's cytoplasm (dark blue) are mitochondria (light blue), which provide the cell with energy. Stem cells are undifferentiated and have the ability to give rise to any of the different cells and tissues in the body.