Book excerpt: Comparative Biochemistry: A Comprehensive Treatise, Volume VII: Supplementary Volume focuses on the processes, methodologies, and approaches involved in molecular biochemistry. The selection first offers information on expressions of the pentose phosphate cycle, including description, criteria for the presence of the pentose phosphate cycle, chordates, segmented worms, mollusks, echinoderms, roundworms, flatworms, algae, and higher plants. The text then ponders on chitin and mucosubstances, as well as the distribution and biochemistry of chitin, molecular structure and function of chitin, and chitin in relation to mucosubstances. The publication reviews the cellular aspects of active transport and hormones and behavior. Topics include relations between inorganic ions, sugar, amino acids, fatty acids, and bioelectric potentials; aspects of the regulation of the intracellular pool of free amino acids; hormones and permeability characteristics of living cellular membranes; and chemical nature of the structure responsible for the permeability characteristics of living membranes. The recording and measurement of behavior, role of hormones in the patterning of behavior, and hormones influencing behavior and the behavior most subject to hormonal influence and control are also discussed. The selection is a dependable source of data for readers interested in the processes, methodologies, approaches involved in biochemistry.