I CYTOPLASM 207 



After destroying the cytoplasm, the tonoplast can be pressed out 

 of the cell as a spherical globule which continues to exist for days. 

 Life, however, cannot be attributed to this sphere, although it may 

 manifest osmotic changes in volume. Similarly, in the unimpaired cell 

 the regulation of permeability by this layer in the usual permeability 

 experiments is not a sign of life, but a purely passive result of diffusion 

 equilibria. 



h. Molecular Morphology of the Cytoplasm 



In this monograph the explanations of molecular morphology have 

 intentionally been kept very vague and general. We have mentioned 

 polypeptide chains and their junctions, lipophilic and hydrophilic 

 groups, acid and basic side groups. These suffice for an understanding 

 of the general properties of the cytoplasm, but its specific achieve- 

 ments cannot be approached in this manner and require a knowledge 

 of the exact molecular constitution. For such an approach, however, 

 only one important starting point is available, viz., the asymmetry of 

 the cytoplasm. Of the stereo-isomeric amino acids only the laevo 

 forms occur in the cytoplasm (Gause, 1936); accordingly, the syn- 

 theses and the degradations which are carried out in the cytoplasm 

 are strictly specific: of the possible isomers, only a particular one is 

 formed. Whereas artificial syntheses of an organic compound with 

 asymmetric carbon atoms lead to an optically inactive racemate, only 

 the dextro or the laevo form of the same substance is formed in the 

 cytoplasm. 



This discovery of Pasteur's is of far-reaching importance to 

 morphology, for it shows how new configurations result from those 

 already present: in the cytoplasm each structural creation requires an 

 adequate creator. This is the principal reason why the cytoplasm cannot 

 be a formless liquid, but must possess a framework of well-defined 

 molecular structure. 



In addition to the asymmetry of the amino acids, which in the 

 scheme of Fig. 87 (p. 132) is evident from the relative positions of 

 the H and R groups, numerous other structural particulars must exist 

 in the cytoplasm framework. All specific physiological reactions are 

 certainly caused by them. It has already been pointed out that en^y^»es 

 must carry such groups of a specific structure. In Fig. 119 an example 

 is given showing the dehydrogenase, which acts as catalytic carrier of 



