Ribosomes during development

Fig. 19a-d. Stage-specific initiation factor during development Tenebrio molitor.In all cases seventh day pupae ribosomal subunits >vere used. RNP was used as mRNA, and initiation protein factors were prepared from last instar larvae of 7-day pupae and used in combinations as described above, a Pupae mRNA and pupae initiation factor b pupae mRNA and larval initiation factor c larval mRNA and pupal initiation factor and d larval mRNA and larval initiation factors. (After Ilan and Ilan, 1971)... 

Several reticula of the r-ER show an ordered arrangement and many ribosomes are attached to their membrane during the primary wall development stage. As maturation proceeds, the r-ER s then gradually decrease not only in number and length of reticula, but also in the number of ribosomes. The s-ER s, on the other hand, become largest after the S3 stage, and sometimes attach ribosomes at their terminals. 

During early development, when cell divisions are occurring rapidly, demand for certain products associated with the translation apparatus (ribosomes) increases. Special regulatory mechanisms ensure that these gene products are produced in the required amounts and that they are not overproduced in the more mature organism. 

This then is the solution of the ribotype theory in order to avoid the error catastrophes in the journey toward exact replication, it was necessary to have high molecular weight protoribosomes, and the production of these ribosomes for an indefinite number of generations was possible, before exact replication, because ribosoids could achieve it with processes of self-assembly and quasi-replication. The development of high-molecular-weight protoribosomes took place during postchemical evolution, simply because all necessary conditions existed in that period, and the development could be realised with processes that were both natural and primitive. 

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