THE QUESTION OF UNIDENTIFIED SUBSTANCES 

 ON CELLULAR MEMBRANES 



J. H. McALEAR 



Division of Laboratories and Research, N.Y. State Department 

 of Health, New Scotland Ave. Albany, N.Y. U.S.A. 



Examples of comraonly occurring structures on the cellular envelope and 

 organelles are illustrated. Included are the components of desmosomes as 

 seen in five major phyla, granules oriented on cytoplasmic membranes, 

 nuclear and outer mitochondrial membranes. Evidence is presetited for 

 an intracellular membrane cément in the mitochondria and Golgi, and the 

 orientation of the éléments of the mitochondrial matrix upon the inner 

 surface of the membranes of the cristae. Hie implication of such organi- 

 zation of éléments, with respect to cellular membranes in terms of the 

 concepts of cellular organization, is discussed, and the technical aspects 

 of the problem of identifyîng thèse structural éléments as spécifie sub- 

 stances or enzymes are outlined. 



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