In prokaryotes, chromatophores are
A. Specialized granules responsible for the coloration of cells
B. Structures responsible for organizing the shape of the organism
C. Inclusion bodies lying free inside the cells for carrying out various metabolic activities
D. Internal membrane systems that may become extensive and complex in photosynthetic bacteria
VerifiedHint: Chromatophores are internal membrane systems present in photosynthetic prokaryotes. In certain photosynthetic bacteria, these structures are extensively found as a colored, membrane-associated vesicle containing different-colored pigments.
Complete answer:
Chromatophores are internal membrane systems present in photosynthetic prokaryotes and should become extensive and sophisticated in photosynthetic bacteria. These develop as membrane lined sacs or thylakoids from the cell wall. Thylakoid membranes contain photosynthetic pigments in cyanobacteria and phototrophic bacteria. Small sacs or granules containing pigments phycobilin remain attached to these membranes. In green bacteria, these structures are typically covered by a non-lipid proteinaceous membrane and they are sometimes known as ‘chlorosomes’.
So, the correct answer is option D. Internal membrane systems that may become extensive and complex in photosynthetic bacteria.
Note: Chromatophores contain bacteriochlorophyll pigments and carotenoids as well. In phototrophic bacteria, like the Rhodospirillum rubrum, the light-harvesting proteins are intrinsic to the chromatophore membranes. However, in green sulfur bacteria, they're arranged in specialized antenna complexes called chlorosomes.
