chloroplast is the site of photosynthesis. It is one of a number of plastids, all of which develop from proplastids which are small, pale green or colourless organelles. Other typical plastids of complex cells are which may develop from chloroplasts by internal noplasts rearrangements. Chrornoplasts are coloured due to the presence of carotenoid pigments and are most abundant in cells of flower petals or fruit skins,