Color enhanced Scanning Electron Micrograph (SEM) showing an oocyte from a rat in cross section. The circular structure in the center is the nucleus, which carries the genetic information. The surrounding cytoplasm contains a wealth of nutrients and information for the initial development of the fertilized oocyte. Numerous cell processes that impinge on the plasma membrane of the oocyte actually contain channels that transmit nutrients and signals between the oocyte and the cells. Magnification: 3,000X at 8x10" print size.