    Sentence What! additional membranes - do  secondary. chloroplasts have?    Sentence. 2The’ engulfed alga ‘was broken  down,. ‘leaving only .its chloroplast, ‘and  sometimes its’ cell” membrane” and “nucleus,  forming. chloropigst with ‘three ‘or four  mhembranes—the -:two . . cyariobacténal  membranes, sornetimes the eaten alga's cell  membrane, and the phagosomal ‘vacugle  from the host's cell mefnbrane.