The interior of either type of cell is called the cytoplasm; in
eukaryotic cells, this term refers only to the region between the
nucleus and the plasma membrane. Within the cytoplasm of a
eukaryotic cell, suspended in cytosol, are a variety of organelles
of specialized form and function. These membrane-bounded
structures are absent in prokaryotic cells. Thus, the presence or
absence of a true nucleus is just one aspect of the disparity in
structural complexity between the two types of cells.