 A second model proposes that proto @-@ eukaryotic cells evolved from bacteria without an endosymbiotic stage . This model is based on the existence of modern planctomycetes bacteria that possess a nuclear structure with primitive pores and other compartmentalized membrane structures . A similar proposal states that a eukaryote @-@ like cell , the chronocyte , evolved first and phagocytosed archaea and bacteria to generate the nucleus and the eukaryotic cell . 
