The animal cell is a typical eukaryotic cell. It ranges in size between 1 and 100 micrometers and is surrounded by a plasma membrane, which forms a selective barrier allowing nutrients to enter and waste products to leave. The cytoplasm contains a number of specialized organelles, each of which is surrounded by a membrane. There is only one nucleus and it contains all the genetic information necessary for cell growth and reproduction. The other organelles occur in multiple copies and carry out the various functions of the cell, allowing it to survive and participate in the functioning of the larger organism.