Figure 11-18. Ultraviolet Absorption Spectra of Various Cell Com- 

 ponents as Measured by Ultraviolet Microspectrophotometry. (From Giese, 

 A. C, 1957. "Cell Physiology," W. B. Saunders Co., Philadelphia, Pa., Fig. 

 10.5, p. 167. After Caspersson, T. O., 1950. "Cell Growth and Cell Func- 

 tion," W. W. Norton Co., Inc., New York, N. Y., Fig. 32, p. 79.) 



the ultraviolet spectra of many organic compounds frequently show only 

 one or two absorption peaks, it is usually not possible to identify a 

 substance entirely by its ultraviolet absorption (Figure 11-19). With 

 the possible exception of tryptophan and tyrosine, which absorb maxi- 

 mally at"280 m//, most proteins of the cell absorb at wavelengths shorter 

 than 230 mn. The high specific absorption of nucleic acids in the 



238 / CHAPTER 11 



