All organisms are composed of cells. The two major kinds of cells are (big/ prokaryote / eukaryote), which lack membrene bound organelles and a nucleus and (small/ prokaryote / eukaryote), which contain membrane bound organelles. The nucleus of eulcaryotic cells is separated from the cytoplasm by a (cellular / nuclear / sticky) envelope. The hereditaly material is in the nucleus. It exists as (DNA only/ / histones only/ chromatin) until the cell divides and then we see chromosomes..