I got this question from my A2 Biology but I can't find the answer. Does anybody know?
Color. Chlorophyll a is light green. The accessory pigments, chlorophyll b is olive green, the xanthophylls are yellow/brown, and the carotenes are red.
Photosynthesis in plants is dependent upon capturing light energy in the pigment chlorophyll, and in particular chlorophyll a. This chlorophyll resides mostly in the chloroplasts and gives leaves their green color. The range of light absorption in leaves is extended by some accessory pigments such as the carotenoids, but does not cover the entire visible range - that would make the leaves black! Some plants and plantlike organisms have developed other pigments to compensate for low light or poor use of light. Cyanobacteria and red algae have phycocyanin and allophycocyanin as accessory pigments to absorbe orange light. They also have a red pigment called phycoerythrin that absorbs green light and extends the range of photosynthesis. The red pigment lycopene is found in vegetables. Some red algae are in fact nearly black, so that increases their photosynthetic efficiency. Brown algae have the pigment fucoxanthin in addition to chlorophyll to widen their absorption range. These red and brown algae grow to depths around 270 meters where the light is less than 1% of surface light. Chlorophylla-a is the primary pigment for photosynthesis in plants. Its structure is shown at left. It has the composition C55H72O5N4Mg. It exhibits a grass-green visual color and absorption peaks at 430nm and 662nm. It occurs in all photosynthetic organisms except photosynthetic bacteria. Chlorophyll-b has the composition C55H70O6N4Mg, the difference from chlorophyll-a being the replacement of a methyl group with a CHO. It exhibits a blue-green visual color and absorption peaks at 453nm and 642nm. It occurs in all plants, green algae and some prokaryotes. There is usually about half as much chlorophyll-b as the -a variety in plants.
primary pigments are the ones the electron involved in photosyn. goes to AFTER hitting the accessory pigs. in order to be sent to the electron transport chain. this is the case with photosystem 2 AND 1, they look like this: kvhs.nbed.nb.ca/gallant/biology/photosystem.jpg the green are accessory, and the blue is where the primary are. hope that helps...im a little rusty since i took AP bio last year.
