Information Content and Biotopology of the Cell in Terms of Cell Organelles 219 



hierarchies of organization; they are sites of biosynthetic and energy yielding 

 cycles (4) (molecuhir 'chunking') large enough to maintain a relative degree 

 of themiodynamic homeostasis and biochemical independence. 



2. Organelles are homologously related in two ways: (a) They are phylo- 

 geneticallv static. Classes of organelles present the same basic appearance 

 in all plants and animal cells: they show synchronic stability. Historically, 

 the chromosome is an excellent example; presently, cytoplasmic organelles 

 including mitochondria, flagella and cilia are even better described than are 

 those of the nucleus. Astbury has proclaimed the demonstration of the basically 

 similar patterns of ciHa wherever they are found as "one of the most important 

 microanatomical revelations of our time" (5), a statement made before De 

 RoBERTis' discovery of retinal rod organization (6) cited below. Basically 

 tubular and lamellar mitochondria are also phylogenetically ubiquitous (7-11). 



(b) They are epigenetically plastic. Organelles react with or respond to 

 their environment and interact with other organelles to produce novel patterns 

 of organelle complexes and systems: they show diachronic non-fixity. The 

 patterns 'develop' from similar mechanics of packing, coacervation and disin- 

 tegration. (A relatedness akin to that described by Thompson for cells and 

 tissues (12).) Thus the nebenkern arises by fusion of mitochondria (13), the 

 acroblast by fusion of dictyosomes (14), the old nucleolus by fusion of young 

 nucleoli (15), the rod sacs and rod tubules of the mammalian retina by develop- 

 ment of the distal region of the connecting filaments, which are themselves 

 ciha (6), the endoplasmic reticulum by fusion of spherical vesicles, and the 

 'prolamellar body' and lamellated grana of the plastid by fusion of lipid vesicles 

 (16). Such earliest reactants we term 'primary organelles'. 



3. Primary organelles arise by synthesis from molecular pools and probably 

 never by division of pre-existing organelles.* The specific pattern has never 

 been seen to divide in nature; it is only replicated. The essential contribution 

 to their progeny of even such classical 'dividers' as bacterial viruses (17) and 

 chromosomes (18) is that of a hnearly ordered code along which new code units 

 are synthesized, rather than that of a code which grows and 'splits'. Experi- 

 ments claiming genetic continuity to centrioles (19) and to blepharoplasts 

 (kinetosomes (20) ) do not demonstrate division of these elements, but only 

 continuity of topological relationships; whereas some primary organelles, 

 microsomal to mitochondrial in size, arise from the nucleus (15, 21) or, in 

 the case of the plant blepharoplast, de novo (22). Hence the organelle is not 

 itself an 'organism' and Altmann's 'dictum' that all granules come from 

 granules does not strictly apply. 



4. Organelles give rise to the gross patterns and shapes of cell parts and 

 of whole cells by symmetrical packing, coacervation and the formation of 

 polarized interconnectives. They provide the periodically replicative units 

 of brush border (23), ciliated epithelium (24, 10) and nuclear membrane 

 (25, 36 — 39); the walled structures of an outer pellicle and an inner cell-mouth 

 (26, 48); the packed units of the cirrus (27), the polarizing units of the kinety 

 (28), and the vehicles of fluid transport 'by which structural lipids move in 

 the cell from site of synthesis to region of lamellar growth' (16). 



* This is to be distinguished from the sort of mitochondrial splitting observed between the 

 miotic divisions during grasshopper spermatogenesis (13). 



