Chairman's Introduction : Remarks on Control of 

 Structure and Differentiation in Cells and Cell 



Systems 



J. RUXXSTROM 



The Weuuer-Gyeii Institute fur Experimental Biology, 

 University of Stockholm, Szceden 



I have the honour of opening the section on " Intact Cellular Structure 

 and Function". 



It must be my first duty to discuss the significance of the title of our 

 section. It could refer to researches in which only intact cells were used as 

 material. I do not think such a study would be very rewarding. Xo biologist 

 would refrain from carrying out experiments. The title may rather refer to 

 studies which aim at understanding the structure and function at the level 

 of the intact cell. With such a definition of our task the essential difii'erence 

 between this section and the preceding ones tends to decrease or disappear. 

 I suppose that everybody who studies, for example, control mechanisms in 

 isolated mitochondria or microsomes has the hope that these mechanisms 

 apply also to the living cell. Let us call such systems models. The more 

 complete these are with respect to cellular components the more they may 

 bear upon the conditions in the intact cell. On the other hand we must be 

 aware that when we go from the study of cell components to that of the 

 whole cell we have to count with new interactions that may seem to 

 complicate the situation to a large extent. 



A concentric approach by difi'erent experimental methods seems to be 

 the strategy to be adopted. Neither of the methods may be able to give a 

 satisfactory answer but an increasing insight may be gained from a com- 

 bination of the different approaches. Sometimes one may also, on the level 

 of the intact cell, distinguish the alternation between complexity and 

 simplicity to which Dr. Kendrew drew attention when he, on the first day 

 of this Symposium, dealt with the structure of the protein molecule. 



For a long time many workers have been interested in the physical 

 state, or let us call it the consistency of the cytoplasm. Before the com- 

 plicated electron micrographs that Dr. Porter has shown us, this problem 

 seems at first sight rather meaningless. It is also generally agreed that we 

 cannot give an overall estimate of the consistency of the cytoplasm on the 



vol.. II. — 2H 



