PHOTOSYNTHETIC MECHANISM OF PURPLE BACTERIA 173 



quantum of about 2 volts once in 100 seconds, about 0.02 of an electron volt per 

 second. Distributing this energy over 100 molecules gives you a temperature rise 

 of only about a fraction of a degree per second. In a few seconds, you can not raise 

 the temperature of a granum more than a degree, if that. 



Strehler: In our circulating system, there was no evidence of a temperature 

 change greater than a few tenths of a degree — for the whole suspension, of course. 



References 



1. Milner, H. W., Lawrence, N. S., and French, C. S., Science, 111, 633 (1955). 



2. Duysens, L. N. M., "Transfer of excitation energy in photosj^nthesis," Doc- 



toral thesis, Utrecht, 1952. 



3. Vernon, L. P., and Kamen, M. D., /. Biol. Chew., 211, 643 (1954). 



4. (a) Duysens, L. N. M., Carnegie Institution of Washington Yearbook, 52, 157 



(1953); 53, (b) 166 (1954). 



5. Duysens, L. N. M., Huiskamp, W. J., Vos, J. J., and van der Hart, J. M., 



Biochim. et Biophys. Acta, 19, 188 (1956). 



6. Chance, B., and Smith, L., Nature, 175, 803 (1955). 



7. Frenkel, A. W., J. Am. Chem. Soc, 76, 5568 (1954). 



