Messengers primitive 231

Of these, (2) and (3) and (1) and (5) must develop together and we see this in Table 2.1. The mixture of primitive cells from which we start our discussion all used as messengers in the cytoplasm various phosphate compounds, various substrates and the levels of minerals such as Fe2+, Mg2+ and K+. We labelled this above system as the P/Fe system of communication in the earliest life system. It may be better to view the system as diversifying at first through combination rather than as progressing. There is a part of the... 

Note K+/Na+/Cl control of osmotic and charge balance while Ca2+, Zn2+, Cu have very little role. TABLE 5.9 Primitive Messengers ... 

As we can see, the features that one can reasonably attribute to the common ancestor are not bacterial ones, but the very features that later, in a more complex form, will be found in eukaryotes. The separation between transcription and translation, the use of stable messengers, and a genome organised in linear chromosomes are all typical eukaryotic characteristics, and yet they are also intrinsically primitive features. 

Messenger S., Amari S., Gao X., Walker R. M., Clemett S., Chillier X. D. R, Zare R. N., and Lewis R. S. (1998) Indigenous polycyclic aromatic hydrocarbons in circum-steUar graphite grains from primitive meteorites. Astrophys. J. 502, 284-295. 

Table 21.7. Some messengers of primitive and advanced cells...

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