Question: why do photosynthetic organisms contain accessory pigments in addition to chlorophyll a?
Answer: All of these various forms of chlorophyll, except chlorophyll-a, are considered accessory pigments because they, unlike chlorophyll-a, can't actually convert photons of light into energy; they 'assist' chlorophyll-a in the energy absorption process and then pass their absorbed energy on to chlorophyll-a for energy ...