Entropy changes are quantitatively evaluated for the macromolecule biodegradation and biosynthesis. Evaluations take into account both the esoenergetic and the endoenergetic components which define the overall processes of the macromolecule biosynthesis. The standard entropies So' of bio-macromolecules are calculated by using a method recently proposed which yields So' values whose agreement with experimental data is better than 4%. Effects and uncertainties are considered for the actual reactant concentrations, for thepH changes and for the different conformations of proteins in solution. Results show that the macromolecule biodegradation, which supplies in animal systems the building blocks to be assembled in new bio-macromolecules, produces an increase of entropy. An even higher entropy increase is obtained in the linkage of building blocks to form bio-macromolecules both in animal and vegetal systems. Among other conclusions, we underline that present results give a strong support to the conclusions of a previous paper showing that the source of entropy decrease in biosystems is respiration, as unique source in animal systems and as primary source in vegetal systems.