In prokaryotes, chromatophores are
(1) specialized granules responsible for colouration of cells
(2) structures responsbile for organizing the shape of the organism
(3) inclusion bodies lying free inside the cells for carrying out various metabolic activities
(4) internal membrane systems that may become extensive and complex in photosynthetic bacteria
(4) Chromatophores are internal membrane systems present in photosynthetic prokaryotes. These develop as membrane lined sacs or thylakoids form plasma membrane. Thylakoid membranes contain photosynthetic pigments in cyanobacteria and purple bacteria. Small sacs or granules containing pigments phycobilin are attached to these membranes. In green bacteria chromatophores are covered by non-unit, non-lipid protein membrane. They are sometimes called chlorosomes.