NUCLEUS 



235 



Gene size according to Muller(i93 5), Fig. izGd (2000)- 50,000 (m/^)^ 

 Gene size according to carrier hypothesis. Fig. 126c 45>ooo (m^)^ 



Target area according to Timofeeff-Ressovsky (1940) 32 (m^)^ 



Chromosome 



Gene 



1.7m u 

 lOmu r 



Fig. 126. Chromosome and genes, a) -v-Chromosome of the Drosophila; b) leptonema with 

 linearly aligned chromomeres; c) leptonema, strongly magnified, with interchromomeres 

 and target areas indicated as points; d) size of genes calculated as prisms with quadratic 

 cross-section according to Muller (1935), each containing a target area in corresponding 

 size, di upper and dg lower limit of gene size; e) gene size according to the carrier hypo- 

 thesis, at the same magnification as d; e^ front view of the gene disc in comparison with 

 a target area, e, ground-plan of the gene disc, indicating the twofold construction out of 2 

 chromatids with equivalent spheres of action;/) yellow respiratory enzyme with apo- and 

 co-enzvme, both drawn on the same scale as d and e. 



Scheme i26e is even more reminiscent than i26d of the structure 

 assigned to enzymes. Fig. i26f depicts the yellow respiratory enzymes 

 on the same scale. Both the size of the colloidal carrier (mol. wt. 70000) 

 of this enzyme and its prosthetic group are known. Presuming that 

 1000 atoms occupy a volume of 3.2- io"20cm^ (Timofeeff-Ressovsky, 

 1 940) and that, in accordance with the composition of sturine (Fig. 

 121, p. 212, 27 C : II N : 5 O : 47 H), the average weight of the atoms 

 of the amino acids is 6.7, the diameter of the apo-enzyme (thought 

 of as a sphere) is calculated to be about 10 m/^ and that of the co- 

 enzyme with 81 atoms, approximately 1.7 m/*. 



