388 RADIATION BIOLOGY 



Furthermore in Chromatium light quanta absorbed by the 800-m/x peak 

 were found to bring about a strong fluorescence of the molecules with the 

 890-mM peak, as did the quanta absorbed by these molecules themselves. 

 Therefore a complete transfer of energy takes place from the molecules 

 with the 800-mM peak to those with the 890-m/i peak. It thus appears 

 that, although several different compounds may absorb energy, the 

 photosynthesis is carried out by a single type of bacteriochlorophyll 

 protein complex. The situation here is strikingly similar to that of the 

 blue-green and red algae, in which only chlorophyll a appears to partici- 

 pate directly in photosynthesis, whereas the energy absorbed by the 

 other pigments is utilized by transfer to chlorophyll a. 



CONCLUDING REMARKS 



In looking at the present state of the field covered here, two points 

 stand out from the mass of accumulated data. One of these is the great 

 inadequacy of the available information as to the absorption spectra of 

 the individual pigments in living cells. The other is the indication that 

 present spectroscopic data support the conclusion that all other pig- 

 ments that absorb light used in photosynthesis act by transferring the 

 energy to chlorophyll. 



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