Many of the intermediate products of respiration of plants are substrates, or synthesis pathways energy source for many other products.

a) The hexoses provide carbon skeleton for synthesis of products which are used in the formation of the cell wall.

b) Triose phosphates are glycerolipids and amino acid base, such as serine and cysteine​​, which are used in the synthesis of proteins and therefore necessary for the production of the enzymes.

c) Phosphoenolpyruvate is the substrate for the synthesis of phenolic compounds, such as tyrosine and phenylalanine.

d) From a – ketoglutarate glutamic acid is synthesized, precursor of cytochromes.

e) From the oxaloacetate aspartic acid is formed, which generates asparagine and pyrimidines, essential for the synthesis of nucleic acids.

f) Erythrose 4-phosphate, which is used in the synthesis of shikimic acid.

Thus, cell wall enzymes, cytochromes, nucleic acids and shikimic acid, are essential in the life of animal cells have their origins in the synthesized by genetic regulation of proplastids circular DNA of primitive plant products as has been pointed out in previous sections worked solo for 700 million years to produce organic carbon compounds (hexoses, triose, phosphoenolpiruvatom ketoglutarate, oxaloacetate and erythrose 4-phosphate), kerogen and oxygen.

Among all interest biosynthetic routes we have chosen the shikimic acid route, develop below for their relevance in the biosynthesis of some pronutrients large veterinary interest.

Shikimic acid, is formed in the plastids of primitive green algae as the result of condensation of erythrose 4-phosphate and phosphoenolpyruvate, and is the precursor for different biosynthetic pathways of aromatic hydrocarbons such as aromatic amino acid metabolites (phenylalanine, tryptophan), cinnamic acid, coumaryl, flavonoids and natural aromatic phenols, all involved in the regeneration of various animal tissues of great importance in the production and animal physiology).

This biosynthetic pathway is specific to algae and plants but not animals cells and is a second dependence biochemical test, animal cells with respect to plant cells, as the animals need of compounds derived from shikimic acid to smooth operation.

(1)    The synthesis of shikimic acid is performed in the plastids of green algae primitive condensation of erythrose 4-phosphate and phosphoenolpyruvate. The result of the condensation is 3-dehydroquinote.

These green algae are the ancestors of land plants (embryophita).

Phosphoenolpyruvate is the substrate for the synthesis of phenolic compounds, such as tyrosine, phenylalanine or auxins.

(2) The production of phenylalanine was also produced in the algae by the incorporation of another molecule of phosphoenolpyruvate in 3-dehydroxiquinote.

(3) The third step is the production of cinnamic acid followed by production-coumaroyl S CoA.

(4) This compound is the precursor of most natural plant phenols.

Thus, the circular DNA of plastids of green algal ancestors of land plants contains instructions to initiate the biosynthesis of substances with regenerative activity will develop in the next sections.