Photoautotroph Algae,Cyanobacteria CO2+H2O Light +Chlorophyll(CH2O)+O2 Purple and green bacteria CO2+2H2S Light +bacteriochlorophyll(CH2O+H2O+2S Photoheterotroph Purple nonsulfur bacteria(Rhodospirillum) CO2+2CH3CHOHCH3 Light +bacteriochlorophyll (CH2O) H2O+2CH3COCH3 Algae, Cyanobacteria CO2 + H2O Light + Chlorophyll （CH2O） +O2 Purple and green bacteria CO2 + 2H2S Light + bacteriochlorophyll（CH2O） + H2O + 2S Purple nonsulfur bacteria (Rhodospirillum) CO2 + 2CH3CHOHCH3 Light + bacteriochlorophyll（CH2O） + H2O + 2CH3COCH3 Photoautotroph Photoheterotroph