Swanson puts it, "view the grand pattern of the cell," which is to say 

 espy the basic pattern of cellular organization in relation to operation. 

 If this day is still well in the future, there are many signs that excellent 

 progress is being made. For example, certain generalizations may now 

 be made with considerable confidence which a few years ago would have 

 seemed premature to say the least: 



(1) Few cytologists or geneticists would now doubt that cellular 

 operation is dictated to a considerable degree by the interrelationships 

 of DNA, RNA, and protein (Swanson, 1957). Indeed it is probably 

 safe to conclude that specific protein synthesis is normally controlled 

 by DNA organization through the intermediacy of RNA, and that the 

 ribosomes (small granules of Palade, "microsomes") represent the struc- 

 tural site of at least the final steps. The details of this interrelationship 

 and how it is controlled are still, however, open questions of great 

 import. 



(2) Electron micrography has taken giant steps toward confirming 

 a long-standing suspicion that all cells are highly organized at the macro- 

 molecular level and even that a basic pattern can be detected despite 

 the enormous variation associated with diverse cellular function. The 

 apparent universality of double membrane systems as shown in the endo- 

 plasmic reticulum, nuclear envelope, Golgi complex, mitochondria, and 

 plastids certainly suggests a master plan and underscores the importance 

 of surface phenomena. 



(3) Biochemical and cytochemical analysis together with electron 

 micrography have combined to establish the mitochondrion, or a rea- 

 sonable facsimile thereof, as the cell's major power plant, and have made 

 it at least as well understood structurally and functionally at the chro- 

 mosome. 



These generalizations, together with others that might be made con- 

 cerning the function and structure of other organized components of the 

 protoplast, such as nucleoli, lysosomes, and plastids, provide us with a 

 fair notion of the roles of the several parts of a cell. A consideration of 

 these several roles may also serve as a basis for construction of working 

 hypotheses concerning integration. In somewhat over-simplified terms we 

 may quite safely assume that information is supplied by the organized 

 DNA of the chromosomes, and transmitted — presumably through in- 

 volvement of RNA — to the site of protein synthesis, which appears to 

 be the ribosomes. Most of the energy for these operations may be pre- 

 sumed to be associated with the production of high-energy phosphate 

 compounds largely supplied by the operation of mitochondrial-bound en- 



270 / CHAPTER 12 



