sentences:  In "Chlamydomonas", the eyespot is part of the chloroplast and takes on the appearance of a membranous sandwich structure.It is assembled from chloroplast membranes (outer, inner, and thylakoid membranes) and carotenoid-filled granules overlaid by plasma membrane.The stacks of granules act as a quarter-wave plate, reflecting incoming photons back to the overlying photoreceptors, while shielding the photoreceptors from light coming from other directions.