Inside the Cell 53 



at Boston have isolated some parts of the process. They have shown 

 that the amino acids are first attached to small unidentified nucleo- 

 tide fragments by the agency of enzymes in the cell sap. From this 

 state they have shown that transfer to the microsomal granules can 

 take place. 



A-B-C-A-B-D-B-B-A-A-C-D Template code of R N A 



: I I I I ■ : I I I II 

 iV </ •/ 1/ 1/ !/ !/ 1/ 1/ I I I - . .J . , 



A— B-C A— B-D B-B— A Ammo acids with groups 



I I I which are complementary 



X Y Z to the code 



I 



A— B-C-A-B— D-B-B-A-A— C-D- Template code 



— X — Y—Z— Small piece of protein chain 



f / / /// /// 



A- B-C A- B-D B-B-A Liberated complementary 



groups 



FIG. 13. How the code carried by the RNA template might operate. 

 Each amino acid is attached to the complementary code grouping 

 which enables it to find its place in the sequence 



These experiments appear to provide the beginning of a solution of 

 one of the greatest mysteries of life — how specific proteins are made. 

 The mechanism suggested is extremely complicated and we can only 

 guess as to hov/ it was established to begin with, but it is clear that 

 nothing less complicated would be able to explain the appearance in 

 the cell of such a host of highly individual proteins. 



