Fluorescent light micrograph of cultured foreskin cells labelled with rhodamine which fluoresces red. The circle at the centre, or near centre, of each cell is the nucleus, which contains the genetic information (DNA) of the cell. The micrograph is labelled to show the numerous long unbranched cytoplasmic filaments, also called microtubules, that form the cytoskeleton of the cell. These intermediate sized filaments, measuring 10 nanometers in diameter, are thought to be responsible for maintaining a distinct & stable cell shape. Magnification: X125 (at 35mm size).